Wish I was closer I have a bunch you could try out.
Timing is a big bog maker.
As you probably know that already.
My timing curves in all my carbed vehicles have been Without vacuum advance.
Quick curves all in by cruise rpm or much sooner.
18 initial at idle has been a minimum for all my vehicles.. from inline 6 mustangs to 302 Ford powered Vans with 6000 lb weight and another 6000 in tow.
Then you find total timing usually start with 35 and work up.
Most of my curves are all in by 2000 or 2200 rpm.
I had to dial one all in 1500 rpm as I had 2.29 gears and 29" tires.. that was fun to do.
If you run vacuum advance and have 24 or 18 initial with it hooked up what is timing cruising down the road ??
What is timing when you punch it from a dead stop.
Not as much when the vacuum drops out.. You could have 10 initial timing and heavy springs and at 2500 may still only have 24 total.
I have had cars come in with 22 total with no vacuum advance old school SBC low compression with 240+ Duration at .050"
That just does not work well at all.
What is your idle vacuum ?
What is cruise vacuum?
I have got rid of the slow to respond by changing power piston springs to stiffer ones.
AFB and Q jet.
Holley carbs usually have a 6.5.
I have found for my cars pulling as little as 11" vacuum at idle really respond to something in the 8.5 or even the 9.5 power valve.
I do not have any bog out of the hole or from a roll or any speed.
Here is a video of what some may call over carbed.
350". Vehicle weight with passengers today would be 3900lbs.
280H comp magnum flat tappet TH 350 4500stall(Cheating I know).
Ported 601 heads 1.84-1.50 valves.
Tunnel-ram and 2 1405 edelbrocks 600 cfm. Stock autozone single point distributor with the point set that came with it and quick timing curve.
Point bounce sets in at a tick past 7000 rpm.
Even with 2000 stall and 3.00 gears this thing did not bog.. it just went.
But really high velocity heads smallish 170cc runners and tall ram is cheating.
It now has an HEI an RPM intake and revs just the same but no issues all the way to 7300rpm.