It's been mentioned or alluded to, but one factor in the original question of RIV/VGF"2" is availability. A lot of people have a lot of different issues with the resale restriction - my issue, as an owner there (and part of the reason to own there for me) and as someone for whom re-selling the contract is not a big factor, is the potential difficulties in booking at Riviera once there are more resale owners who can only book at Riviera who will likely be booking in the 7 - 11 month range. That's the only way the resale restrictions impact me as a direct Riviera owner (owner - not seller). It has the potential, however, to have a rather substantial impact.
That being said, I think that's actually a reason to go with RIV over VFG in this case (especially since you already own a significant # of VFG points). The new "VGF2" addition should make it easier to get into VFG at the 7-month mark, whereas having RIV points to use at 11-months will likely only become more important to have if you want to book at RIV, as you have stated to be the case.
So, since, at least theoretically, VGF should get easier to book, and RIV will likely only get harder, it makes more sense to get the RIV points in order to have that option - especially given how many points you already have to be able to use at the 7-month mark. It would seem "diversifying" and adding the option of RIV at 11 months makes the most sense for your "portfolio" of points.