My experience with them is they are a little longer than the Flats I used historically from Curtis.
I initially used a Template but fcg holes were not "cock on"
What I did eventually, was dump the Templates, Trim the back of the Receivers to achieve same Overall length as a Curtis Flat and use a Caliper to mark and drill hole location. Everything came out spot on.
Not used the Curtis Drilling fixture , so can't comment.
All other stuff from I've had from Curtis is A+++++++, Especially the trigger Guard Drilling jig for rivet removal. I've used that little tool for removing all AK rivets without a problem. Best $25 ? I've spent in a long while.