I am now retailing these too and decided to try some for myself.
First, the C Products SS mags are a mother to drill through. I had to go buy some titanium bits after ruining the ones I had around.
Second, the C Products followers are going to stop you from getting all of the rounds into the magazine. I had an easy fix. I just used my bench grinder and cut a big notch in the middle of the front leg of the follower. It doesn't affect the magazine function at all and the mag works just fine.
Then I figured out that I really didn't need to drill through my magazines at all. Just install the Kit A through the magazine floorplate hole in the bottom!
The Kit B went into my Bushmaster 10/20s no problem.
I mainly use a lens pen with a machine bolt in the lid as my Bullet Button tool, but too often I forget it at the range. Now with these on all of my ten round magazines, I shouldn't have any problems.
For $6 a four pack, you really ought to have these on all of your ten round magazines.