If the gage is right I wouldn't even think about it. We ran it at 700 and it was fun. It's a little different experience than the rest of the poudre. Also, u talking about running upper or lower?? Suppose it wont matter much, neither of em are going now.
ps-go do the rustics if you haven't, they wont run too much longer.
DOH, nevermind, I see you said the the upper, your gonna need a bit more water