What can one say about a translucent sheet of greaseproof paper (not actually greaseproof, I tried it in the oven and it didn't make my cakes taste that nice)
Jokes aside, this isn't that effective at diffusing the light. It makes things slightly dimmer, and blurs the focus of the LEDs, but that's it.
The PAR can I bought didn't have mounts, so it sucked sellotaping it to the side.
Pros - Someone might find it useful
Cons - didn't work that well, poor mounting system, bit of a waste of money for me.