Two tubs of mice isn't much work (1.2 and 1.3). It's been cheaper for me WITHOUT getting any litters dropped yet already, for just two young corn snakes. However, I plan on expanding to more corns and a few balls. If you're going to expand, I say go for it. If you find it's not working out, you can always stop. And, if you have your breeders stop suddenly and need changing out, you can just order some bulk. My 2 cents here.

Honestly, I think that if you have picky eaters, you should breed. 6-10 tubs is more than you need, I think, (unless you plan on selling off extras or need a lot of adults) but it's not too much work except for occasional culling, cleaning weekly, and a daily check.