Left at 12:30 am - 10 hrs to summit
We acclimatized by doing
1. Mt. Lassen (~10,400) on trip down
2. Went up to Bristle Cone Pine Forest and did a ~5 mile easy day hike @ ~10,000 feet 7-1-19 and slept at Grand View Campground @ 9,000 ft that night (had hoped to do White Mtn, but road was a bit iffy)
3. Hiked up to Trail Camp on 7-3-19, which was also useful for getting a sense of trail for nighttime hiking
4. Stayed at Whitney Portal night of hike
5. otherwise trained in WA state by usual method (very steep hiking - 1000 ft+/mile, but not necessarily at altitude)
The hike up to Trail Camp was useful not only for acclimatization, but for orientation relative to approach in dark
We used switchbacks for perceived efficiency relative to effort, at 67 years of age and not having been above 10,400 ft in 30 years, I was somewhat anxious about altitude issues vs. effort
We had no issues with the trail in the dark, and although we used the traverse someone else mentioned just before Trail Camp on the preliminary hike, we approached through a gap on summit day which was much easier. This involves leaving the trail (climbers left) by Trailside Meadow, attaining the rock ridge and continuing up on rock/snow to Trail Camp.
The lower switchbacks were snow covered, and there were a few places where a switchback was still snow covered, it was relatively easy to pass through and regain trail
The Cable area had a section where you had to drop under cables (awkward moment with poles catching cable) and traverse on snow/rock to a corner where you scramble up about 6 feet to regain trail. Although there are plenty of foot/hand placements here, this is a no fall zone. In the morning, there was a small snow platform to move across for feet, but by afternoon it had melted out (unless you're 6+ feet tall) and you had to move over/back up to trail on very wet rock (it was a very cold shower at corner down climb!) The rock is of such good quality (and there was a couple of thin flakes), that it was easy (it helps if you have rock climbing in your past)
Beyond that, there were a couple of snow traverses to Trail Crest which were well established - we hit Trail Crest before people who started from Trail Camp at same time but went up the Chute. Beyond that it was a longish hike to summit.
The snow is melting so fast (there were noticeable differences even over the course of the day), that this probably not relevant anymore.
The scenery is staggering beautiful, Trail Camp at 5:00 am with the early morning sun on the Whitney massif was jaw dropping - truly the "Range of Light"
The traverse under the cables was my favorite part of the hike, lol
Evidently there was a 7+ magnitude earthquake that pm, our legs were so pounded by the hike that we didn't feel a thing!
Thanks to everyone who has posted information here, having some sense of the "lay of the land" was very useful