You can flip a 50cc bike over, if you really want to.

The clutches are designed to take a bit of stick.
When racing, the usual mechanical sympathy rules take a back seat.
If you want to win, I don't see how you can take off from the start line without giving the clutch a good amount of slipping? If the bloke next to you slips the clutch and tears off down the track. Then you pull away like you're on a Sunday drive to the chippy, then clutch slipping man will have the advantage.
Of course, if you aren't racing then it's a different story.
I used to get some lovely wheelies out of my 300 mc21. 1st, 2nd and 3rd gear power wheelies.
When we did the Llandow track day it was going at a fair old lick all day when Wayne and myself were "not racing" each other. I didn't have a problem with it wheelying or trying to flip over at any time on that day. Completely standard gearing in the gearbox and final drive.
If you're getting uncontrolable wheelies from your 300, it's probably not the fault of the bike.