Tribbia reports as follows (fleshing out the route). Note that 47m59s was the time read from his stopwatch, slightly different from what Strava reports (as usual).
This route starts at the parking lot of South Mesa Trailhead, heads up Mesa Trail, then left on Homestead, uniting back with the Mesa Trail and connecting to Shadow Canyon, and finally up the South Boulder Peak Northeast Ridge for a true summit of South Boulder Peak. Most certainly this is not the route Dave Mackey ran his sub-45 ascent and probably not the shortest route from Trailhead to Summit, but I chose this route because the currently published FKT Ascent (51m 3s) uses this combination of trails.
After a route inspection run last Friday (5/4/18) in snow on the upper portions of the route and coming close to the published FKT, I decided to give a proper effort for a fast ascent in close to perfect conditions. Trails were not muddy, no wind, crowds were minimal, and 60-degree temps. The only damper on the conditions were the nuisance of gnat-like bug swarms at the summit. Watch time from the parking lot gate to true summit was 47:59 -- I started my watch from the back of the parking lot to make sure I would capture the segment. Splits based on glances at watch: Trailhead to the base of Shadow Canyon (19-high to 20-low minutes), from the base of Shadow Canyon to Saddle (22-low minutes), Saddle to true Summit (5-low minutes). As I mentioned in the route description, this is definitely not the route Dave Mackey ran his sub-45 ascent and probably not the shortest route from Trailhead to Summit, but I chose this route because the currently published FKT Ascent (51m 3s) uses this combination of trails. Hopefully, there are no issues with using a different route than Dave's, but if there are I am okay with that and absolutely love the lore of those days pre-Strava. (I wish Scott Elliot would tell us all of his times/splits!)