I also finally managed to build my Velobuild TT-023. Attached a photo of the finished bike.

Here is my setup:

Frame: VB-TT-023,  1022 euro
Bottom bracket: Senicx ceramic t47 bb, 44 euro

Wheels: Elitewheels 80mm, 370 euro
Tires: Vittoria Corsa Pro G2 TLR with TPU Ridenow innertube, 101 euro
Rotors: RT-CL900 dura-ace, 45 euro

Groupset: shimano Ultegra/dura ace di2 12 speed for tt bike, 1004 euro
Chain: SUMC oil slick 12s, 48 euro
Cassette: ztto 12 speed oil slick, 26 euro
Powermeter: Stages R8100 170mm, 231 euro

Saddle: Pro stealth aero 132mm carbon, 90 euro
Bottle and cage: Elite Crono CX, 31 euro
Pedals: Ultegra R8100, 48 euro
Garmin mount: Closethegap raceday evo fi, 60 euro

Tools: misscelanious, 46 euro

Total: 3166 euro

The installation process was quite easy. Most exciting part was cutting of the fork (measure ten times, cut once). The cable routing was very easy. The only downside I have noticed so far has to do with the cassette. The Ztto cassette doesn't shift as beautiful as an ultegra cassette.

Yours might twist, sooner or later. I designed the following fixation.

Is it possible to share the 3d file? Really like this fixation and want to use it.