if your a 1 man band prob get away with 350,
but if have space and load carrying ability I'd go
bigger. you don't have to fill it more than need,
but got a buffer then.
when I got reels brushes etc from Gardiners just
asked them what spares would need, the
suppliers are the professionals, after all, so
should be able to tell you.
good luck with the transition, it's a good move.