Bending 5mm acrylic (Perspex) sheet would indeed require practice before committing a large piece to the heat gun. The gun must be kept moving or blistering may occur. Not too close to the sheet or it will become damaged, i.e. slowly does it.
Thinner sheet is a lot easier to handle. As for tapping the stuff, a tapping made into 5mm would work but it would not be strong, regardless of thread pitch, though as suggested earlier, a coarser thread would be preferable.
I used Tensol cement for school projects - No. 10 is thick because it contains dissolved Perspex, so it is rather treacly in use and can be messy. Pure solvents can be applied using a syringe for accurate location and minimal overspill.
Again, at school I used a strip bender which was simply an electric fire element set a little way below the gap created by two metal surfaces. The sheet was held in place by hand until the sheet became pliable. Very easy to do, provided the element length wasn't exceeded.
Strip bender:
https://www.abbeon.com/Item--i-1257
Tony