That T-port sync looks pretty good; from square to slightly taller than wide.If the secondaries had to be cranked quite far open to achieve this, then the engine wants more initial timing. But as you have discovered, with your current dizzy set-up,this causes the dreaded detonation.
The cure for that is to limit the centrifugal advance. You say your advance is now 14/34. Well that means there is 34 - 14 =20* centrifugal. If you rework the dizzy cam by shortening the advance slots, such that the new centrifugal is say 16*, Then when you reinstall it and reset the power timing to 34*, then the initial will be 34 - 16 =18*. The engine rpm will go up 50 to 150 rpm, depending on how it liked the new idle timing. This will allow you to close the secondaries back to a normal idle speed, and reset the mixture screws. This should improve tip-in from idle.
On the otherhand; if the secondary cracking screw is only open 1/2 to 1.5 turns, then you are pretty close. Somewhere after 2 turns, if the rear has no idle fuel compensation, then the carb often exhibits a problematic idle, a stinky exhaust and,lean tip-in, that requires pumpshot fiddling. I try to run as little pumpshot as possible cuz well, pumpshot sucks fuel.The extra idle timing also fills out the low-speed timing curve and often helps make a snappy response, until the timing is all in.And best of all, the extra cruise timing and leaner A/F at cruise will help get some Mpgs.