I've been shut done twice on West Face due to weather but I was totally on track to finish as a dayhike. Bummer, had to ski all the way back to Bunny Flats with no summit in hand but superb non-stop skiing for 6 miles!
BTW, a day hike or an overnight hike? Well that depends on a person’s objective. I like three approaches: 1) one day hike, 2) a couple day hike with a base camp somewhere in the middle, and 3) 2-3 nights (depend on circumstances) taking all gear to the top and spending one night on the plateau or close to it.
Time is not important, 4-7 hours, more or less; who cares (well some may). Having a good time and coming back intact is important. I believe there was a guy who climbed Shasta 5 times in one day. Do you want to match that? So climbing Shasta only once in a day is not a big deal at all. Or is it?