I had some issues but none that were insurmountable. Moulding the shooter-lane into the protector caused some problems.
The heat from lights in my case was negligible as I only had 14 alternating lights under the playfield, only 7 on at a time and never for long. Additionally I had replaced all the inserts with acrylic discs. The combination of thicker insert material and LEDs meant that in the time the machine is used the temperature of the playfield does not increase. The machine is also an EM so the heat output from the box is tiny.
The material I used was 0.75mm PETG sheet so about 0.029 inches. This can be cut with tin-snips or large scissors easily but I chose to use the method I did as I wanted to remove any chances of messing up like over cutting or slipping.
Wire roll over switches can be easily adjusted and the chances of hangups on mine are the same as on the original playfield as the protector is identical. Star rollovers are a different story and I have not had the joy of dealing with them.
The rollover holes on the pre-made ones seem to be shaped to accommodate playfield variations and expansion.
Reasons for doing this…
In my case I did not have the option to clearcoat and the playfield seemed to be contaminated with something causing random reactions. Most of my playfield was repaired with decals so using a sheet protector was my ideal solution. I also wanted to see if I could do it.
My concerns…
Summer. Is the increased ambient temperature going to cause it to pillow / bow? - This is always going to be a concern on a captive protector.
Humidity. What effect is this going to have ?
I will just have to wait and see.