In the manual it suggests setting the speaker size to "Small'. My receiver has a "Large" option, but the rest are specific frequencies - e.g. 150, 120, 100, 80, 50 (I'm quoting from memory here). Which do you recommend as "small"? And should all the 3's (I have a 7.1 setup) be set to the same level?

Yes, those are the choices for "Small", there are so many different ways that receiver/processor manufacturers describe the speaker setup options it is impossible for us to give specific recommendations in the manual. We rely on our dealers for that service when selling our product. Also, many of today's home theater receivers include a room EQ system that often chooses frequencies for you.

With your specific receiver, 120 or 150 Hz would be the correct choice with SuperSat 3's, and this can be the same for all the SuperSat 3's in your system (in some situations a higher crossover on the surrounds and rears and lower on the front may be appropriate). The crossover setting choice depends on the subwoofer location (and quantity), room size and desired listening levels. I'd suggest starting with 120 Hz on all SuperSat 3's and see how it sounds.