Be sure you can reach Wide Open Throttle if you upgrade your carb to a larger size. A lot of people have been disappointed on what they thought would be a performance improvement by upsizing the carb and having it go no faster then before.
The stock Moby throttle is good for 15mm lift without modification to the twist if properly adjusted, with further machining needed in the grip guide for any more then that opening.

Thanks for that, it made things a lot clearer

With the type of twist grip on my 50v (And I assume many others) could one maybe mill out the slot on the twist grip bit to give a wider range of throttle openess?

Yes you can mill out the / slot on the grip to allow more travel but you are limited to how much by the actual slider which follows the / because as it pulls it travels towards the actual rubber grip on the grip, so you are limited by that. I do not suggest going more then 16mm anyhow and a little mod to the / will allow that much travel.
If you go for a larger carb then that for a AV10 you will need to either make a bellcrank for the carb or swap the original twist grip for an aftermarket one like a Magura - and also purchase a 'starter' lever to replace the decompressor you will not have when you swap out...