I have a single speed so my MO is to gather any momentum I can find before the climb, stay in the saddle as long as I can (I move back on the saddle), and then finally stand on the pedals to crest the hill. I run about 78 inch gear as a compromise and find that if I let my rpms drop below a certain point it's a whole lot harder going slowly up the hill as opposed to mashing.
-G