As far as removing the set screw for the adj. sear, I think it’s pretty much impossible (by design) after red-loctite the high thread pitch and the tiny size of the Allen key mean even if you super heat it the red loctite won’t be able to leak out of the part so you will just be breaking Allen key after Allen key. I’ve tried briefly and it became clear there wasn’t going to be any easy way.
Good news is, for two of my low rd count SP01’s that were fitted for adj. sears to the stock safeties, when I replaced it with another brand new extended safety, no fitting of the new safety was required. I was also running a CGW extra strength detent spring (before and after safety change). When I tried swapping in another, older extended safety that was well worn it was not interfacing with the adj. sear So it likely depends how worn-in the original safety that was fitted to the sear was. Give it try before buying a new sear I would say.