the 68 of course. The ironman has a longer seatpost and the seat is a good 1-2" over the stem (both set to min insert depth). With a taller stem it would be more comfortable but it feels fine riding it, I just am leaned over more (more aero!).
this is what my haul looked like when I got it home, btw
also got a set of alloy drop bars and 2x titanium water bottle holders.