I own the Mistica. It has a provision if the one you buy includes it, a behind seat rack. I don't run that for time trial, but do in training. I actually put three bottle racks on the seat rack. One for the saddle bag and then two bottles.
The Mistica has a bit more rounded edges versus the older Tritone. People complained the edges of Tritone were a little harsh sometimes.
"For the money" versus a brand new nicer ISM, the Mistica was my choice that I stick with.
As for that Aussie TT bike:
Whew, nice! I like the detail of the color matched aero large RD cage setup. Very clean cable free bike. The cheapest way into full on aero skewers are "Pinheadz" security skewers. They use a locking pattern similar to what you see on his bike at a fraction of the cost. I've actually not seen anyone near me running Cadex anything yet. We're not ballers, so there's that. But still, it seems like by now I would have seen some of the new Giant branded deep wheels around on a Propel or something. Interesting also still seeing wheels go from 90mm front to trispoke back to 90 back to quad spoke........ that Cadex quad spoke reminds me of the older Shimano 4-Rays. Then Shimano went to the trispoke. One of the legacy mysteries there was fork interaction of the spokes and what fork spacing was optimal for them. I wonder if with the modern stuff they considered that.
I saw an old narrow width HED 3d the other day go for $1k on Ebay. That's the 90mm deep trispoke they made. I think it was 90mm deep on the rim profile before hitting the spokes, weird looking thing.
I had a line on an older Trinity SL Pro local to me that was 10spd Di2 that was just a RD purchase from being 11spd. Looked great. Dude wanted way way too much though for a bike as old as it was, and he was the third owner. Some that are 6 years newer were going for less on Ebay that were already 11spd. If bonus pans out how they're predicting, I may go with a Trinity with Di2. Wait out the "Covid boom" till later summer when numbers come down and people go back to blowing cash on concerts, games, and stores other than bicycles and folks have done those "bucket list" triathlons.