Interesting. We were always at least square jetted (same numbers all the way around)....but usually 2-3 numbers HIGHER in the rear.

Put thermostats in changed the jets to 80's in the front and 86's in the back had it running on trailer took it out on the lake and ran if you could get it to go. Died all the time going into gear would not idle down but ran fine around 3000 rpm. It got us to Kellys where one died then the other, one would not start again, the other finally did. Came back from Kellys on one motor, that died at the ramp. My carb project is not going so well, lol.

If you only run a PV in the primary, none in the secondary, you need an 8-10 jet split front to back. If 96 is correct in the secondary you should run 86-88 in the primary.

The initial stumble off idle sounds like it could be an accelerator pump problem. Get 50cc accelerator pumps if that is not what you have.

You need to remove the flame arrestor and with the engine idling see if fuel is flowing into the boosters. There should be no fuel flow visible. It sounds like the float levels are not set right and flooding out the engine(s). If there is fuel flowing you will need to adjust the floats down until fuel barely drips out of the side site screw hole. The precise setting of floats need to occur with the boat floating in the water.

I agree about the float setting. If the float level is high the engine will run rich and you may get drips out of the venturi boosters.
Usually a mid range bog is caused by the float setting being low.
The fuel in the bowl needs to be high enough to cover the correct air bleed holes in the main metering circuit for mid range metering.
Main jetting is only rich or lean at high speeds, not mid range speeds. The engine is not pulling enough fuel through the main jets at mid range speeds (partially closed throttle blades) to utilize the full flow capacity of a (to large) main jet.
You can only be rich or lean (from the wrong jet) at wide open throttle!
Dennis Moore

I'm with Griff, accel pump issue....try a 37 squirter, make sure the cam you have is a decent one and watch for a good shot when opening the throttle(not running) the 1st 1/2....jetting is all another deal....

Sounds like you are in over your head and need someone who knows holley carbs well to help you. But if you don't know someone who can give you real help then here are a few things I wpould suggest doing.These aren't that hard to work on or make run right There are quite a few things that could be your problem, sounds like you have a off idle stumble if I am understanding you on top of a slew of other problems. I would start by:
Buying a how to tune your holley carb book and reading it
dissassemble carbs, clean them and check power valves/gasket alignment
set Float levels, check accel pump stroke/shot and that the checkball holds
check all spark plugs as you may have some dead ones if its running rich
set idle using a vacuum gauge
stagger primary jets to account for no power valve in rear, a 850 typically uses 78's to 82's on primary, if it was mine I woulkd put somne 80's or 82's in primary and some 88's or 90's in rear to account for power valve plugged off and jet my way DOWN watching exhaust temps/plug color
verify fuel supply pressure and volume
make sure someone hasn't swapped gaskets or jet plates for the wrong ones and blocked off a passage or something, Smitty