I used the SolarEZ- Very happy so far - not sure if it will last forever but it only took a couple hours to do an entire playfield of inserts. I'll be doing another before too long.

Interested in the transparency too - I tried clear vinyl which curls upon contact with the resin, so no good. I've thought that acrylic or lexan might work and keep things super flat and intend to try. If those work, I'll try to get circles of appropriate size cut out of them so that I can cure JUST the resin on the insert then easily wipe off the excess.

I didn't use it - it hardened fine.

FYI - I bought the Solerez and found it a little thick and sought out the advice of the maker. Here is what he said:

"This resin is already pretty thin. If you heat it up in the microwave (8oz 1/2 pint for about 10 seconds each time until it gets to about 120°F, like very hot bath water)

If this is thin enough, we have a vinyl ester resin that starts off at this viscosity. It is clear too. But heat is an easy way to "dial-in" your required viscosity without diluting"

I haven't tried it yet - just sharing.