You need to take the Pilot Air adjusting screws into account as well, when you're trying to get a good idle; just remember that turning them clockwise
makes the mixture richer, since the screws are regulating air, not fuel.

For setting the idle I find it necessary to decouple the linkage between the two carbs; otherwise the there is unwanted interactivity between the two carbs idle settings. Once the idle is set for each carb I connect them back to the common throttle linkage. It's a good time to check for sticking or binding in the throttle linkage as well.

I would suggest that you do not use the throttle linkage stop on the manifold; leave the throttle linkage free-floating. I typically sandwich a nickle between the tab on the accelerator linkage and the throttle stop on the manifold while I am making adjustments. Once adjustments are made and the nickle is removed the tab invariably moves a little closer to the stop; but doesn't quite touch.

Yes, Mikunis seem to like to dribble gas out of the float chambers, maybe it's the ethanol in the gas, maybe they don't like being mounted tilted sideways on the manifold, maybe they don't like proximity to the exhaust manifold, maybe they are motorcycle carbs and have no business being mounted on old Volvo motors.

Definitely do everything you can to keep the float chambers and fuel hoses as cool as possible. I will be making a more extensive heat shield one of these days, to see if it helps any. I'm already using a ceramic coated exhaust manifold, and a cold air inlet hose using a modified 140 series HIF6 airbox
with two Kuryakin airbox adaptors.

Lastly, make sure your fuel pressure is under 3 PSI. Don't use Scantech fuel pumps, use one of the sealed Pierburg pumps. If you must use a regulator, don't use one of those chrome plated dial adjust ones that sell for $23-30, get one of the Holley ones that cost $90 or so that people use with DCOE Webers.

Please keep us informed, there is too little practical information on the Volvo/Mikuni conversion.

Bill