I buy mounts in strips. For sizes below 33mm (fits many stamps), I use top loading mounts. I will purchase HAWID 33 size and then trim the height. The cost for 25 to 33mm has been the same so I deal with fewer different mounts.
I have a tray to store mounts.

I use a crafter's glue stick to attach mounts to avoid moisture from licking mounts.
When I used to use hinges and licked mounts, I used a little swap to apply moisture. You really want to use as little as possible.
