You can run a stock 49cc jug carb and proma on 78 or an 80 if your on a high flow filter.
The shocko is only sorta close to 60cc and if the carb and intake stay stock with a proma and shocko, thats gonna be the 82 or the 85.
Mayyyybe 88 but I bet that gets four-strokey on the flats unless your "porting" is actually legit then yeah, I'd start with an 88 and test up/down one size each way for lowend, midrange and wot.
I wouldn't expect 90/92 unless you were really killin' it with an aggressive map or boost ports etc. (edited)