Rythmik F12 vs. F15 for small room

I am debating between the F12 and the F15 for my 1330 c.f. room and am wondering what is recommended. Dina told me via email that the F12 is adequate for a room under 3000 c.f., but then I just ran across a statement by Brian over at the AVS forum where he said this: "In addition, the decision between 12" sub and 15" subs should also depend on the woofer size in the front speakers. If the front speakers also have 6-1/2" woofer or bigger, there is no point of using 12" subs." My main speakers are the Focal Chorus 807v's, which have 7" woofers, so going by that, I should get the F15, according to Brian's advice. Further info - this will be a 2.1 system used mainly for music, but some HT, driven by an Outlaw Audio RR2150. Thanks in advance for any advice...

In that size room, and for music, the F12 will be more than fine.

That's what I was thinking as the only apparent advantage of an F15 would be increased output, according to other things I've been reading. I have an F15 on order with Ascend, but it increasingly seems like overkill so I'm thinking I may downgrade the order to the F12. Thanks for the comment.