Hi AstraKid.

We tried and tested foils but eventually settled for reflective glass. Its more expensive, but the end product is far better.

Just a few tips:
Foil on Perspex - Forget it. It will eventually bubble and look crap.

Foil on Glass - OK result, but difficult to find a foil that gives a good balance between reflectiveness and screen brightness.

Reflective Glass - Shoot for a 50/50 if you can - 50% reflectiveness, 50% light permeable.

Good luck.