I'm running an SR Race exhaust which is a Sip Road 2 clone.
P200 air cleaner, under seat air filter removed
2020 carb, undrilled
55/160 idle, 160/BE3/100 stack
I felt like the Stella's stock E3 mixer didn't work as well. I probably am running it a bit rich but I don't have plug fouling issues and I don't seem to have any significant flat spots, bogging or surging.
These are the slightly modified Bald John settings, which many here now find to be antiquated but they work well for me.