I've got a pro bp ten II, I like the pistol but wished it had a officer length grip. Lately I've been thinking about chopping the grip down.  My question is what magazine would work?  I know that the p14 fits and works in the fullsize guns with a little massaging of the mag catch notch, but which para mag would be egual to the officer size gun?  Also is there a difference between the mainspring cap and plunger of the government and officer model?  And finally what would be the best way of gauging where the new hole should be drilled in the frame?  I've built some nice 1911's before, but never chopped one.  I have chopped the grip on a G17 down to 19 proportions.  I guess measuring the distance between the holes on the mainspring housing from the top of them and then transcribing the dimension ( roughly7/16", the difference according tospecs in brownells mainspring listings, measure more precise if  I order a housing) to the frame and drill.  If I go for it I'll drill before I cut so that I know it runs flawlessly, if it doesn't I've got some acraglass and black dye, fill my holes and forget about it.  Any suggestions or answers to my questions would be much appreciated.  I got to good of a deal on the pistol to pass up, thats why I didn't get the compact ten instead.  

The equivalent length Para mag would be the P12-45 mag.  The MS cap and plunger on the shorter Ofc. ACP MSH are larger in diameter.  It sounds like you have the right idea on drilling the hole.  Also, if you are going to re-texture your grip, you might consider dyeing the whole frame afterwards in a liquid dye bath composed of RIT liquid fabric dye.  It penetrated into the resin about 1MM, and makes everything match perfect.  The ratio is 3 parts black to 1 part dark green.  Post pics when you're done.