Are you all using integrated handlebar of velobuild?
I ordered without handlebar because I prefer to use stem+handlebar… I’m 85kg and I think is a more rigid option.
My idea is use or FSA SMR stem with ACR system or Deda Superbox stem.

https://www.bike24.es/i/mb/b3/58/d2/fsa-smr-stem-6-degrees-932944.jpg
https://hollandbikeshop.com/img/prod/deda-superbox-potencia-a-head-1-1-8-o31-7mm-90mm-alu-negro-8052783488041-11-l.jpg

They offer a stem and handlebar combination since today I believe.

Make sure to use compression free housing.

I guess I don't need to know what "Use: spare axle (rear 12 x 148 mm)" means. 

My frame is out for delivery as I type this.

It's a copy paste from the shop, bike components, website.

So, after the first few rides and tinkering a bit with setup, brakes etc I'm Really happy with the bike. It rides really well, handles nicely and predictably and is comfy for long rides (3h +).
In direct comparison with my other bike it takes slightly more effort to keep up higher pace. I wonder if I'd notice if I would not have been able to ride the bikes back-to-back.
It also "feels" slightly slower generally but I think that's due to the different tyres, where I ride this bike on vittoria corsa controls at 29mm wam (5 bar ~70 psi). The other bike is rim brake and I use pirelli race 27mm wam (5.4 bar, ~80 psi) . Power wise it's not noticeably different at anything other then the above mentioned higher pace. Maybe the extra 0.5kg also matters slightly.

The build is a mix of GRX and Ultegra components, due to availability and cost as well as preference for hood shape, ergo wave braking and (now it finally functions) the clutch on the rear derailleur for the "light gravel" round I intend to ride too.
I routed the shifter cables outside to prevent shifting issues (it shifts better then my other mech shifting bike where everything runs internally).

Main components:
1056 frame (58) and 1036 handlebar (11x42cm).
Grx 810 shifters, hydro brakes and rear derailleur.
Ultegra 50-34 crank175mm, 11-32 cassette, Rd8000 front derailleur and hg701 chain.
Ultegra pedals.
Farsports Feder 45mm, 28mm outside 21 inside on carbon ti hub, brass nipples and cx sprint drive side spokes (unbelievably light combination), vittoria corsa control 28mm, latex tube.
Xtr rotors 160mm front and rear

Small parts:
Sq labs active 612 14cm
Close the gap garmin mount + bell
ZTTO handlebar tape (very much like lizardskin, recommended!)
Tacx bottle holders
Bontrager flare light

Total weight 8.3kg


Issues while building :
The front cable guide  , with the new guides in the house I'll replace it with a proper one as soon as I feel like swapping the front derailleur cable.
The rear axle drive side "holder" was tight. Replaced it with one of the spares and problem solved.
The lower screw of the front brake caliper is quite tight, I guess some resin left over, it works and holds well however it was not super easy to get the caliper in perfect position.
And I forgot to add cable foam on the rear hydro brake cable  brakes are super tight now so I don't feel undoing "just because".

Left to do:
Find rubber grommet for the hydro hose entry point on the front left, which I don't use. Anyone know a fitting one?
Decide whether I want to go down another 5mm or keep it like this.

I've bought Robert axle project axles
172mm and 120mm
Perfect fit.

That's interesting. The guide I received with my 1056 rather looked like the one on the bottom. There was a small fin on the rear side but only a few mm long and w/o cable. In combination with the fitting issues I'm wondering whether I received the correct one... anyway now it is installed and working. I will receive a bag with some more spares and am now curious how the two BB guides wll look like.

Yes, I got a similar one to the description you give. The small protruding part broke when installing. So that Is a third configuration. It looks like the longer extended type cut short.

Looks really cool!

As an update: the grx rear derailleur fits easily with the clutch On when paired with an 11-32 cassette. It was indeed the B screw.

@Aesch - I've had it with an Ultegra RX dérailleur that the positioning relative to the cassette was off. It was how it was sitting on the hanger. Unlike some of the road dérailleurs, it's quite easy for something to be misaligned when installing.

So. Just checked everything, it is on right, connected straight. Hanger is straight. If I screw in the B screw it works to clear the stays but not necessary with the current 11 28. I guess if I fit a 11 34 or something it will work.

I Checked clearance too, I have >6mm of clearance on both sides of my current tyres. These are 29mm width as measured.