Hey, Congrats on your PT-1911, you will love it!
I have had my Stainless Steel version for just about 2 months now and have 1000+ rounds through her with no malfunctions. I did put a dab of blue locktight on the threads of my guiderod as the was backing out after 50 rounds or so.
My safety has been great but some have a loose fitting ambi... In that case I would suggest taking the safety out and using pliers (gently) on the left hand side notch to bring the arms together to get a tighter fit.
As far as grips, I went with the Crimson Trace Laser grips and had no problem with them fitting... I did have to use my dremel on the right side safety to get it to clear the laser diaode but that took a whole 30 mins and was not an issue for me really... I think most grips (Govt) should fit with nothing more than minor adjustments.
No clue on the magwell (sorry)...
My PT-1911 has been a dream so far and is spot on accurate, I hope you have as good of luck
And remember the ol' saying... If it ain't broke, don't fix it.