"16 to a 21 a week ago on my minarelli without changing anything else i noticed a huge improvement in my midrange. like drastically"
You didn't specify what sort of carbs you went from? If I went from a 16mm guntner to a 21mm phbg... sure.
If you saw an improvement in the midrange, that means you need to spend more time figuring out jetting. :-) Your needle setting was very poor on the 16mm carb.
As part of the "small carb brigade" I'll be buying a 15mm next week. ;-) And a nice small intake to match. You should run the smallest intake you can before a reed valve to get the best carburation.