40" bows out quite a bit if you run it straight out, but it can be done. I prefer 36" for this, makes air sharing nice and comfy.
Halocline, I guess as a big guy I've never been able to run a 5', and the 7' actually is a bit snug without an angle adapter, but to me I'd rather stuff the hose in my waist strap or under a canister light simulator in open water if I'm going to bother with it. It is much more comfortable and I've seen that from many other people. That all said, I don't use a long hose unless I'm in an overhead, I've been using a 40/44" with angle adapter since 2009 for backmount in open water. The only real disadvantage to this is you do have to clip it off any time you take it out of your mouth since it can't lay on your neck or shoulder.