As a guide on the Poudre i think that 2.5 is fine to take a 14 foot raft down, it may be a little slow to go from Steven's gulch to BTO, but everything is runnable. Watch out though, it's really technical right now Claires rock is flipping lots of rafts as well as the tooth rock in Pineview, it's no float trip(at least with a boat full of guests).
Regardless of the flows, I am going to try and fit my 15' oar rig from upper through bridges. It will be light, with two people and a dog. Our raft is a Superbug (STAR), floats well in 6" of water, and can float over rocks 6" out of the water(as long as we stay straight). I can report back to you after the weekend.
Low flows and Bridges: I think it was 2002 during really dry period we were running Bridges in OC's at just over 1' on the rock. I remember small commercial rafts coming down the run when we were on it. Although these were desperate times, I think it shed some light on what can be done at 2-2.5' on the rock in terms of smaller rafts.
Claire's rock is just downstream of Ouzel picnick area, big pink rock, right of center, kinda looks like an igloo from up stream. The tooth rock is in the last drop of pineview. A foot off line there and your whole raft is enjoying a cool swim. 2002 definatly made us realize what you could get through, it's fun, but a bit slow at times