jets

Jet question,
1100i motor, (crank fired ignition), new 40mm dellorto’s long velocity stacks, lm111 headers+balance pipe, short straight through megga’s.
Carb’s came from Germany jetted for free breathing 1100, little test today it pulls well from tickover to full, checked plug’s and they looked a bit lean, looked at main jets 148’s in there put some 152’ s in that I had lying around, definitely pulls better high rev’s, how big a jet do you think I need?
155’s in my 1000s, runs Good tickover to full, 160’s maybe for the bigger motor?
Any info appreciated,
Phil

First thought occurs to me try increasing in steps, when performance becomes worse, the previous size is the one. Plug colour as well of course.

Update,
Did some research on other site’s and it seemed that 165s were the way to go… got some put them in, rough running with black smoke…
Conclusion, the Germans new what they were delivering and the 152s hit the spot.
Result