If you camp at Black Rock and get a pretty early start, you wont get to Ranger Station till after Noon as I recall, maybe close to 1pm. Not bad if you plan on doing an overnight in WW, makes a bit of a late start for doing WW in a day run. Won't see the wind till the afternoon usually though (WW / Windy Corner)
There shouldn't be much difference between 5000 and 4500.
Nothing in the world is more yielding and gentle than water. Yet it has no equal for conquering the resistant and tough. The flexible can overcome the unbending; the soft can overcome the hard. - Lao Tse