im just wondering what would be good jet sizes to go in a 32/36 weber running drawthru on a supercharged a15?

Stock jets, but a couple of sizes bigger on the main jets is where I'd start.

Beyond jetting, since you'd presumably want to get it to have ok part throttle economy - instead of going up too many jet sizes, you can also downsize the air correctors. This will make it go richer up top a flow increases. Normally this would be way too rich on a non boosted car, but for turbocharging or supercharging, you actually want it to go richer up top, richer than it needs as far as fuel to burn, as some of that fuel acts to cool the intake charge a little bit further. So reducing the air correctors can do wonders. Don't go ridiculous, 1-2 steps smaller on the secondary, and 1 on the primary to start with and see what that nets you.

and whats the best way to make them smaller ... im having problems sourcing them

A trick some people used on blowthrough carter afb carbs (and I know yours isn't blowthrough) was to get some thin piano wire and slide them into the air corrector, then twist the other end around a screw on the carb body, or the air cleaner stud, then a few blobs of araldite or similar to secure it to that post. if you bend it right it will stay in there.

I should point out that in a blowthrough, you reduce the air corrector size to about half the area (not half the diameter) which is more substantial than you'd want to go with a drawthrough (due to their own particular idiosynchrasies) so you'd want to use the thinnest wire you can find. It will still be reducing the air corrector size more than you'd probably want it to, so if you have to do it by this method, only do it on the secondary.

here's a couple of pics from the old blowthruturbo list I was on. Obviously the appearance and location of the air correctors (called 'air bleeds on most big 4 barrels) are different, but the concept is the same