I sent off orders for a Rock River Arms 9mm upper assembly and 9mm hammer from Steve at Adco Firearms today. Brownells is sending a Hahn Precision dedicated magazine block.
I've also ordered some CProducts 9mm magazines from 44mag.com at the "pre-election price" of $16.99 each. Hopefully they will work with the Hahn block. I've not had any hands-on experience with either nor have talked face-to-face with anyone who has. I gather CProducts has been changing follower designs. I don't pay too much attention to what I read on forums.
"Product XYZ is crap, the customer service is terrible, and I'll never buy anything from them again." For some reason, those complaints reminds me of guys who over-adjust and break rear sights when they have trouble hitting gigantic B-27 targets at 10 yards.
So it is a leap into the semi-unknown. I will not yield to the dark side of the farce and use a Dremel tool. I promise. I save that for precision dental work. ;)