I do not like Flow, but if you're stuck on rear-entry bindings, just go them. Personally I just don't get the point of combining a traditional 2 strap system with the rear-entry like they do with Bent Metal, Roxy, and K2 bindings. Extra weight, more slop, having to re-position the ankle/toe strap each time you put it on...kind of reduces the possible benefits of rear-entry.
15 NS Ripsaw . 14 NS Proto HD . 14 NS Cobra . 13 Gnu Space Case EC2 . 2013 Salomon Pow Snake
14 Now Drive . 13 Now IPO
14 Flow Hylite