Man, I don’t get it. You should be doing way better than 35. I can get better than that with a stock top end, pipe, and carb, with stock gears, just by changing the air filter and tuning the carburetor. You should be low-mid forties easy, even with the Proma. It’s not a high revving pipe, only about 8,000 rpm’s, but still. I can’t figure out what you’re doing wrong.
I do think you’re a bit optimistic in your expectations, but it should be performing better than it is. You are definitely over clutched. Two shoe, with kickstart springs is my go-to for stock and mid performance builds. If you were closer, I’d give you a hand with it.
One more thing; you have a clone carb. The carb body is fine, but have you changed to genuine Bing atomizer & slide? Make sure you’re using good internals, because the clones are tough to tune unless you replace the guts. I see you said it’s a 2.17, I don’t know if a 2.22 would help, but you might try it.
Your timing is at 17* you said. That’s okay if you’re stock, but I’d rather see it around 14-15. But to do that, you’ll have to file/dremel the mounting screw slots in order to rotate the stator plate far enough. You’re gaining on it. Keep at it, you’ll get there. Just remember, small adjustments make big differences with an engine this small, due to the small volumes of fuel and air it consumes.