I'd keep them in a separate coffee can until I had enough to reload -- at least 100 of 'em.
I would *like* to find a bunch of .45LC cases that take small primers so I could switch back and forth between .357 and .45 on my reloader without changing the primer feeder. That would be handy. (but not handy enough to cut down Casull cases
)
Unless you load right at the bleeding edge of the load data (either the high end or the low end) I don't think the primer size will make any difference in anything you'd load in a rimless pistol case.