I have tried the Corsec bases for my civilian ships. They work fine, until you add something to mark the centerline, whether that be my firing arc stickers, or just a painted on line. What happens is that every stem's threads are different in that if you just pick up a random base and stem and attach them, you don't get the same alignment every time. So you can be up to 45 degrees or more off of the centerline when you tighten up the ship on the threads.
I learned the hard way that tightening up too much is a no-no, as the stress of tightening up will cause the base to split right in half.
So you basically have to have a dedicated base and stem "matched" to each ship, which is a pain in the rear, though it is doable. The expense is not insignificant either, when you look at what the bases+stems cost.