BS34 KZ750L (very similar 1982 GPZ) jetting

Bike is set up with Kerker 4to1 with KN filter in stock airbox. All else is stock.

Currently has 40 Pilot with 115 Main. Runs better with these changes over the stock 37.5/110. It never really idled super smooth (before or after jetting) and has always been a little slow to warm up until it doesnt need choke. That's why I went to larger pilot. Currently seems to idle highest/smoothest @ 5 turns out on the Pilot air screws which I don't understand....but I thinking the carbs are due for cleaning as bikes been in storage a while since jetting changes.

Any rules of thumb pilot and main combos with this setup is greatly appreciated along with corresponding turns on the air screws?

You should not need to go up on the pilot at all. You should go up 2-3 on the mains. The pilot should start out at 2 1/2 turns from a gentle bottom. I tuned these on my GPz.
The Mikuni carbs are extremely sensitive to clogging the fuel passages, much more so than the Kehins.
You might be able to get away with spraying carb cleaner down the passages, but the best way to clean them is to strip and dip.

5 turns out means you need a still larger pilot jet

It is also an indicator that the passages are partially clogged. The Mikuni carbs are very sensitive to clogged passages.
When I tuned my GPz (pods, pipe, Stage 3 kit) I tried to go up one size on the pilot jets and they were too large. I ended up going back to stock and the pilots were just fine.

Ok so here's how it worked out. Cleaned carbs without individual disassembly so used standard spray cleaner method.
Used compressor to blow out passages.

I've rebuild these carbs over a dozen times this way over 33 years owning this bike. What I've NEVER had to do before is mess with the float levels. They were way low. Thats why I couldnt figure out what was going on this time. Floats not leaking just needed leveling. Now they're spot on.

Idles better than it ever has and runs smooth as new. Using a Carbtune (way easier than my former mercury Carbstix) sync device is a must as changes in balance are SUPER sensitive . Kept jets as noted in past post. Air screws ended up at 3. Starting at stock of 2 out from bottom. Then turned in finding rough idle point and then turning out to highest idle. Divide by 2 for average equalled 3.5 for me.

Maybe next rebuild/cleaning I'll finally disassemble and soak a few days or just move up another size in pilot jet.