Store in a cool spot for up to 1 week. I tend to not keep them beyond this point as things start to go stale. It can vary on the time it takes to go stale, so it’s up to you to test and know beyond the 1 week point.
If you use bigger treat bags, you’ll either need more ingredients or you’ll just end up with a bigger leftover tufted tail on the treat bag. Totally up to your preferences. I liked the tail leftover on the bags to be smaller.