If you're going to let it sit, in my opinion, I would go ahead and bottle it and let it sit in bottles, since it should be bottle conditioned anyway. I'd be interested to read the opinions about secondary aging versus bottle conditioning. For my BDS I did two week primary, two week secondary which is my normal MO for all beers, but then tucked it away in bottles. It's been in about 6 months now, looking for a year.
I would be a little scared of those kinds of volumes in homebrew as well, I've used 2.5 volumes for my bottle conditioned Belgians and it seems to be fine on carbonation/frothy head/head retention levels. It certainly doesn't "seem" undercarbonated to style.