That's a good schedule. If you make it to Trail crest, obviously note the time, say 9am. After that keep track of how long you're walking along the west ridge. If you're going 1mph, you'll reach the summit @ 11am. If not, that's your turn-around time regardless, because you should be shooting for a return by 1pm at the latest.
To tell you the truth, for people coming from further away and with limited time, if the conditions aren't favorable, it's sort of a cluster-fvck. It's one thing to attempt in the summer, but another thing in the winter/spring.
IMO, a much, much better option that provides as much Sierra beauty as possible, and is (as near as can be in the Sierra) completely safe, is to simply hike up to Kearsarge pass. (TH is just 15 miles north of Lone Pine.) Other than Horseshoe meadows, this might be the best acclimatization hike anyway.
It's a little under 5 miles to the top, starts @ 9k and tops at 11.8k. So, warmer, less snow, lower elevations, no equipment necessary (maybe micro-spikes with trail runners; heavy lugged boots solo should be fine). And the views are perhaps the best in the entire range - looking west from the top into Kings Canyon Nat'l Park:
