340 Initial timing questions

I'm busted,lol.
But just to maybe ease your mind; my cam is an old Hughes HE3038AL flat/hydro. Specs are 276/286/110 and lifts of .549/.571 (1.6arms) and using their 1129 springs shimmed up some; enough to hit over 7200 without losing control.
The thing is, this engine has accumulated over 100,000 miles. The idle has never been set higher than 750, usually 700 (stick-car), and it has spent probably dozens and dozens of hours at 700 down to 550 rpm, cuz you know how those cams sound idling around at the car shows with retarded timing,lol.
However, I made a couple of mods, cuz, like you I was worried about the lobes. I increased my oiling to the topend for spring cooling, and cut some drain-back channels in my Eddies, and I drilled holes beside every lifter bore to let those factory junk-collecting low-spots dribble oil into the cam tunnel. Additionally I run a high-volume pump with a Milodon 7qt roadrace pan, and it's pick-up. And lastly, I always add one small bottle of ZDDP at every oilchange running any old dyno oil. I'm not kidding; whatever is on sale.
So with over 100K miles on her, Ima guessing it's working.

I don't run vacuum-secondary carbs anymore. Or carbs with air-valves. I'm not dissing them, I just like my 750DP; my car does what I ask it too, when I ask it too, and it's totally controlled and modulateable with the pedal.
Oh, she's a 3.09low Commando box with a GVod, that I use as a splitter. She runs 3.55s and 65=2240rpm (this is 110kph our Manitoba highest speed-limit, only found on the TransCanada hiway).
The fun gear is second gear where 32mph is 2700; well it is when the tires aren't spinning.That's one of the advantages of VP around 155

I'm glad you got the off-idle tip-in sag cured; that can be really annoying.