Reach of Dual vs P2k

So, I’m ready to join the Cervelo cult. I’ve been pouring over the messageboard and the Cervelo site trying to pin down a good fit. I know the answer of which I should get is the one that fits best. There are no good tri-bike fitters in/near town, and the LBS is just starting to supply Cervelo, so doesn’t have any in shop yet. My size won’t be available for a few weeks, so I have some time to think about it, and maybe even get to a fitter, somewhere. I do want to get on it soon though, so I can get used to it for IMFL.

I’m (maybe slightly under) 5’10", 140 lbs (1.77 m, 63.5 kg), very approx 31" inseam, and quite flexible. So I’m in between 650/700 (prefer 700 due to current equipment, but willing to go either way), 52-55. Currently on a 52 Cannondale R3000 (was fit for either a 52 or 54, went 52 with a longish stem), 53.5 top tube, saddle stays in my road position for triathlons (<–not in the standard dictionary, heh), Aerolite clip-ons, so I’m way too stretched out, up too high (it’s really a bad, bad position), but I still manage decent bike splits and runs.

I want to be at 78 (or more) deg. Seems like on the P2k, I’d be on either a 52 or 55. I’m worried that on the 52 I’ll be too far forward, and on the 55 I’ll be stretching too far. The 54 dual seems like a perfect fit in between to me – 52 p2 = 525 top tube, 422 reach, 55 p2 = 540 tt, 432 reach; 54 dual = 530 tt, 418 reach.

I’m not looking so much for a fit here (although I wouldn’t mind opinions either), but more wondering about my thoughts on the dual being a fit in between the two p2k’s? Also, if someone could explain the differences in the reach #'s for the two frames. Oh, and I’m planning on swapping in a one-piece areobar deal, the new HED looks awfully fun, I’m guessing it’s adjustable enough to make it work well on any of these? Thanks.

Jason