I'd done the Nesakwatch Enchainment in different variations several times: climbing the SW ridge of North Spire into the traverse, scrambling the saddle between and backtracking to do North Spire, and also scrambling the NW ridge of North Spire into the traverse. In total, I've climbed each peak 5+ times using different routes and I have a high degree of familiarity with the micro-terrain of this particular route. Note: for the FKT, the NW ridge is the accepted start to the traverse.
I wondered if it would be possible for me to do the route alone, while making it feel within my "control" - I didn't want to feel like I was out of my comfort zone or take unnecessary risks. On a bluebird day-off, I packed my helmet, a rope, climbing shoes, and some gear into my bag, packing my approach shoes for most of the scrambling.
North Nesakwatch I was quite comfortable with, and I knew exactly where to go for the easiest ascent (still exposed 4th-5th class terrain). I reached the summit and scrambled down to the saddle. For South Spire, I followed the easiest path (mid-5th to ~5.7 in spots), but ended up not using the gear as much as I was prepared to until the summit plateau. The summit block is unprotectable without a #6 cam, so I have always solo'd it with a rope to rig a TR for a partner and to lower off. It didn't feel too different alone, so I put on my TC's for the off-width and climbed without a belayer below me, just a rope tied to my harness. Lowering off the top, I swapped shoes and did a second rappel into the notch below Rexford. I found a new-to-me path up from the col, which involved some choss and steep scrambling (4th-5th class) to gain the "West Ridge" route. I reached the plateau, and for good measure tagged the middle summit on my way to the true summit. For what it is worth, I went up the chimney pitch to reach the summit of Rexford, and used the bypass on the north side to scramble down from the summit. It is in better "style" to complete the traverse using the chimney pitch on the way up Rexford, rather than the bypass. I also popped over to the third false summit for good measure before scrambling down the west ridge, across the boulder field, and down the approach trail.
This is a fantastic route, and I would highly encourage climbers to go do it, even if not for an FKT attempt. In fact, you should try it first before giving the FKT an attempt, probably even more than once. I have intentionally left out gear specifications to allow attempters to discover their own beta for route and gear, and also to avoid someone copying my gear list and sending it without learning the intricacies of the route for themselves.
There is a creek at ~1200m that the trail crosses which flows year-round, which is great for water on the up/down as needed.
**NOTE: I cropped my Strava activity to start/end at the old parking lot of Rexford/Slesse Memorial. In the case that the road is fixed, future attempts will be able to start from here, so I removed the ~300m from the beginning and end of my effort (since I parked at the washout). My time from washout-to-washout was 5:48:31 (still saved on Garmin Connect as this). My time from parking lot - to - parking lot was 5:41:28, which is what I have submitted as the FKT.