"Anyway- put her on the water and got more bogging mid range - expected from residual premix- but smoother acceleration- a little bit of a bump to wide open throttle but much better than before. "
In a pinch, I make gaskets from single ply department store shirt box cardboard, especially for testing purposes or if I'm anticipating being rough on them.
We're dancing on the head of a pin when we're at the point of final tune, it's better to be conservatively rich with hint's of 4-stroking than lean (hesitation). It's not clear whch of these you're experiencing, perhaps bogging means slightly rich?
Easy warm restarts are part of a low speed mixture screw adjustment goal. We're shooting for a happy balance of crankcase fuel at low speed where idle RPM aren't trending down and need a throttle blip to clear out excess fuel collecting in the crankcase.
If there's too much fuel, plug fouling becomes the issue. If there's not enough fuel, detonation occurs (detonation becomes an issue at speed where heat is produced, not an issue while idling and putting around). Detonation will torch pistons with heat and the clue presents itself as hesitation.
It concerned me a little too; I don’t think it’s of much note but I’ve been running with just the flame arrestor on and not the airbox- maybe that will help a little with the PTO carb but it’s probably going to make things worse for the MAG.
Both mag and PTO should have the same color assuming both have equal time on them. Installing the factory breather richens things up, ie: without the breather a lean condition (with perhaps hesitation, even) can be anticipated.
If you have one cylinder loading up on fuel (black fuel soot is an indicator, brown is a normal color of decomposed oil), it's time to confirm a reasonable pop (which can be accomplished without removing the carburetors).
That's my understanding, the 787 was tuned slightly fat part throttle. It's important to differentiate lean vs comfortably fat though.
Another aspect that seems encouraging in this case is there's no mention of the engine falling on it's face and quitting like it ran out of fuel (too lean).