125-200cc sms 125 carb

What carb is the best to run on my husky sms 125 its currently got a dellorto 28mm, what is the best manufactor? And best size to run it?

I just did a bit of a search and most seem to fit 32 - 34mm flat slide mikunis
Also noted that some say the power valve is fixed in the shut position, but as I have never worked on one I really cant say if this is true
OKO carbs that are copies of keihin flat slides can be bought for less than £50 new so thats a option (they are well made)
I must add you should do as much research as possible on the subject because if you dont know how to correctly jet a carb it could all end in tears