Ugly beast had its debut race on Sunday.
Since the pics above I had it back in road made for a while, then back to aero mode, and left one spacer under the stem, so it was 10 mm higher than pictured (no race day photos unfortunately). Used it for commuting for several weeks to get used to the position. I'd say the main benefit of this is getting your neck used to the strain, and learning to turtle or peek over the top of your glasses...
https://www.strava.com/activities/85545402620.3km in 33:49 (officially 34:16), including 4 hairpin turns and dismount. So above 36 km/h average, closer to 37 km/h if you ignore the run out and last corner/dismount. Kept the pace very even between first and second halves (Flyby shows I dropped a few people on the 2nd lap

)
Really happy with how it rode (run is another story - stomach cramps from km 1 to 3). Comfortable, stable, kept up with some (and passed many!) much fancier bikes, which is always satisfying. Easy enough to shift from the aero bars.
Finished 20th of 86 in my age group, happy with that for my first full sprint distance event. Reckon I could have been about 15th if my run wasn't affected (tip - full strength gatorade is not good on the bike; compensated with too much water in T2).
Next steps? I might squeeze the saddle a little further forward (there is about 1cm between the limit mark and the point where the rails bend), as I did slide forward on it a little (easy enough to slide back occasionally), but otherwise the ISM is a really nice place to be.
Some longer aero extensions would be nice as they are too short for me (were cut short as purchased).
If I can find some ABS sheet I might hack up an aero wheel cover. The rims are vaguely aero (30mm) but real eggbeaters with 60 spokes to whirl...
Next event is Corporate Tri (only a 10km bike leg) so I might drop the stem lower again.
And keep working on the engine of course!