I have a Baldr mini on my Hellcat and love it. As noted, take off the rail and just put the screws back in, and it'll fit perfectly. I did go to Lowe's and got a small screw, to replace the big flipper-release-handle (I want to say it was an M3 screw? - and I use it with the factory spring-and-nut on the other end). And I LOVE the rechargeable battery - I have power in my gun safe, so the magnetic charge puck simply lays on the shelf where the gun spends the night. Simply wave the Baldr near the puck, and it hops in place on its own to charge. Then just pick up and remove the gun, and the magnet lets go. Slick.
I will check out the mckinatec page - good link, thank you! I have Alien Gear IWBs for my XD-s; I bought some kydex and made my own shell for the Hellcat with the Baldr, and put it on one of my Alien base panels and it works pretty well...but I can tell it's not "professionally done". I did manage to luck into the right mold pattern so that it automatically activates the Baldr when I draw - not sure how I did that, but I'll take it!
I did take a dremel tool to the front of the Baldr, to round off the (large!) square corners, to make it a little easier to re-holster. So far, it's been working well for me - retention is good, draw is good...and my kitchen stopped smelling like hot kydex after only about 2 days