I, too, favor the "hump" of the rounded mainspring housing to a flat mainspring housing. That's easy. Go buy a rounded mainspring housing and switch out the mainspring detent plunger at the bottom of the spring, the hammer strut plunger at the top of the spring, and the mainspring and mainspring retaining pin. To disassemble, you put the housing in a padded vice and get a good hold of it and depress the hammer strut plunger with something soft like a big nail. While it is depressed, push the pin out with a small drift punch or finishing nail. Release the plunger slowly and remove it and the spring for swapping into the new housing. The latter is assembled by reversing the process.
As to the beavertail, that is tougher. Many beavertails require a frame alteration, shortening and rounding the recoil frame profile (protrusions behind the thumb safety pin). You can't really put that metal back. If your beavertail was the drop-in kind (no alteration) then you can just put a GI grip safety in its place. You may have to do a bit of filing to trim the step in the end of the blocking extension to get it to work properly. Using the GI type with the altered frame will function, but looks a little odd and may bother your hand more. Personally, I prefer the beavertail because the standard safety makes my hand sore in the thumb-to-index finger web after a protracted shooting session; but everyone's hands are different.
P.S. I looked up a photo of the PT 1911. The frame is the altered style, though the safety does not ride as low as the
Les Baer and has not got complete coverage of the underside of the frame so it doesn't completely prevent annoying contact with the thumb-to-index finger web. You might find that design suits your hands better.