Bill, couple other things to help you tap:
Make sure that your tap drill is the correct size. Many times, numbered drills in sets are a couple thousandths undersize, leaving you an undersized hole. Getting 70% thread engagement is great, if that is really what it is. With an undersize bit, you might be trying for 90-110% thread engagement.
If possible, use your drill press for tapping. Getting it started free-hand can lead to an off-slant tap.
And, as you noted, good taps are always cheaper in the long run than less-expensive taps.
Are you goin g to blue, or brown your triggers? I am usually undecided about coloring the trigger plate itself, but I do try to rust-blue the triggers. Great rust protection.