Too much timing?

At idle, and keeping the speed constant, just tug on the V-can until the speed no longer increases. Now you have found the optimum idle timing at that rpm. Don't be surprised to see the timing climb to deep into the 20s and higher.
If you continue to add advance past the optimum point, the speed goes down because the crank is no longer in the best position to receive it so the pressure is trying to ram the rod into the crank instead of turning it.
Think of it this way; remember as a kid blowing on one of those whirlygigs you made in play-school? If you blew at just the right angle. you could get maximum speed. Same idea . You set the initial, to get the max pressure to the crank when it is in just the right position.
But that is at idle with no load on it. Just one condition of millions of possibilities.
I keep telling you guys, as to power, the engine doesn't hardly care what the timing is, until the stall rpm, and then doesn't care, as long as the curve is fairly linear, until full-power,WOT at about 3400/3600. That is the zone we have to concentrate on getting right. With 3.55s and 27s, and in 2.45 low gear, this happens between about 18 mph and 28 mph.
That is where your power-timing has to be spot on, erring on conservative every single time..... because this is the zone your engine will spend most of it's life.
now; lets say the power-timing has to be not more than 24* at stall of 2400. and not more than 34* at 3400. The rpm range is 1000rpm, and the timing range is 10degrees. That computes to 10/1000 X 10= 1.0 degree per 100 rpm. That is your mandatory maximum power-timing curve. Now for a pair of same length springs, extrapolate 1 degree per 100, back to say 1000 from 24* at 2400. I get an idle-timing of ;
(2400 less 1000/100) x 1.0=14 degrees beginning at 1000rpm.
Ok now; I don't care what you set your idle-timing to, but if 24* at 2400 is the max, with single-stage springs rated at 1.0 degrees per 100 rpm, if it is not 14* at idle; it will be DEAD WRONG from stall to 3400. And remember, in the example I used, these are the MAXIMUM.
Next, go put your engine on the dyno, and measure it's peak power with optimum timing, then with 3 degrees too much, then with 3 degrees not enough. Firstly; the engine will lose more power with 3* too much timing than with 3* not enough. But more importantly, what are the numbers? Sometimes the numbers are so small as to be almost meaningless. But lets say you get 7hp at 5200 rpm. Now go back to 2400rpm. Take a guess how much power you will lose with 3* not enough timing, at 2400rpm.
But you say, what has power-timing to do with what I feel at PT at under 18 mph?
Answer; EVERYTHING. For a HotRodder, your Power-timing has to set the tone/be the baseline, for all your engine's timing needs; and the thing we use to flush out the timing for PT use, is the Vcan. With a decent compression engine, you can modify your Vcan to supply up to 24 degrees over and above the power-timing at any rpm between idle and say 3400, rpm depending on how you the tuner set it up.
So with just 14* mechanical timing at 700rpm, you could change this to 14+24=38*@2400. And say you are taking off normally and the 24* stays in all the way to 3400, where it is now 34+24=58*; or
Say you floor it right off idle. the vacuum falls to below what you have set the V-can to, the engine spools up to stall(2400 in my example) and the beast takes off. or
Say you are just motoring to the icecream store, at some modest power level, and the Vcan is bringing in only 12*. Now your timing is say 18* mechanical plus 12 in the can =30degrees.
Lets suppose that in these examples ,all of them are acceptable to your engine with no detonation. I mean you tuned it to be right.....
Now; tell me again , how an initial Idle-timing of more than 14* in this example, would be helpful.
In these examples, all the settings are such that the maximum pressure in the chamber is delivered to the crank at or just after the decades old proven best point, in the which the crank can transfer that pressure in the most efficient way. Neither more nor less timing will produce more efficiency nor more power, because you the tuner, have paid attention to your engine, never mind what some guys on the internet tout.
If you build your timing curves on the wrong baseline, you will never get it right. And for a street HotRod, the V-can is your engine's best friend.
And you know why?
Because, your engine will spend it's entire life, except maybe 1% of it, at some other throttle position,less than WOT; so why worry about 7 hp at 5200rpm much less 3hp at 3400, much less on the power at sub-stall rpm, which you can easily manipulate with either the V-can, or with throttle position.

And finally; you have got to set your transfer-slot exposure just right, to prevent an off-idle tip-in hesitation. The transfers should be your primary low-rpm and idle fuel supply.
If your slot is too small, the transfer fuel will be reduced in volume, (which you can augment with the mixture screws for idle, and the idle will be just fine), and the transfer fuel delivery rate will slow down, which, at tip-in, will take time to start up again, ergo the hesitation.
If an automatic, going into gear, the new load will be too high for the starving transfers, and the engine will just stall.
After setting the transfer slot exposure, the only way you have of setting the idle-speed, is with idle timing. So, if you start with some, in my opinion, fantastic Idle-Timing, your exposure is GUARANTEED to be too small. If you do that, you will pull yur hair out trying to keep the engine from stalling when you put it into gear, and it will be impossible with pump-shot, to solve the tip-in hesitation..
Don't be that guy
At the risk of pizzing off a few gurus, forget about targeting fantastic Idle-timing numbers; 12 to 16 will get your transfers into the ballpark. Then after you get the Power-Timing worked out from stall to ~3400/3600, start dialing in the Vcan to give you back the PT timing your engine will crave.

Btw, in my examples, YES, I biased the numbers to prove my point. Your targets are specific to your engine, and 1.0degrees per 100rpm may not be achievable with your parts; don't be thinking your combo wants or needs 1.0, let her tell you what she wants. To do that, I installed a dash-mounted, dial-back, timing-retard box with a range of 15 degrees. Which made it fairly easy.