Pumped OS 200 is about 50 grams lighter than YS160, so you need to lose some weight to make the change.

8200rpm with 18x10 sounds quite a lot for OS, my 200S is hitting 8100rpm with APC 16x12 and 30% nitro. Anyway pull is decent with my 4750g plane.
Try a smaller prop before making any bigger changes. Give for example 16x12 a try, your engine should turn it quite a bit and not lose rpms so much on uplines.

JE