The Mikuni pilots work in that carb, run a #25. The Keihn OKO round slot head mains work, run a #110.
That is about what everybody around here runs, works really well and helps the bike start 100% easier and smooths out all the full rev range on the carb.
Any big bike shop should have these jets in stock, usually around $ 2.00-2.50 per jet.
Hope this info helps you out.