Can you unscrew the big axle and take a picture of the internal space between the bearings? Check if there is a spacer there?
In such manner :

This might take a while.  Don't hold your breath. Not my bike.

I just remembered I posted a picture of the top link a year ago in reply #22 of this thread. See if it shows something.

Maybe I'm not getting what this is for, but can't you just put two separate spacers on the outside of the bearings using the existing through bolt without redrilling the linkages?

Can anyone confirm that a piggyback air shock like the Super Deluxe will fit in this frame?

In my correspondence with BXT, the rep claims that piggyback air shock won't fit in this frame. It looks like the piggyback might fit similar to the hightower as long as the air can fits in the ~50mm width of the shock tunnel. I've attached the images the BXT rep sent me.

The rep said:
The dimensions of the shock seem wrong, and maybe the rep is just trying to sell me the deluxe inline shock they carry.

My son has this frame and I do not know if a piggyback shock will fit since he does not use a piggyback shock.  And Fox type air shock with a piggyback will probably fit, but a coil may not.  YMMV. The shock is definitely a 210x55 standard eyelet and the bushings are 24mm as I stated in reply #21 of this thread.  Do a little research on how shocks are mounted so you know what kind of hardware is needed for the shock.  There is nothing propietary about the mounting on this frame.

You will need to buy a headset with cups.  Nothing is "integrated".

For extra dropouts use the "142" 12mm  thru axle variety.   BXT has standardized this type of dropout on other frames including those with non-boost 12mm thru axle spacing, but they never bothered to update the listing.

ok, I read that they work with mineral oil, what type of oil do you use?  overheating problems?  Thank you.

I've bled them a few times with shimano mineral oil.  I regularly do steep 2000ft fire road descents. They have never overheated and fade is detectable but minimal.  These brakes are decent.

What's not right? It looks pretty good to me.

Cables through the headset: yes, it's a bit of a pain when you're building it, but worth it for the clean lines
People are talking about the seat tube length: it's shorter than a Genius, Epic Evo and Anthem Advanced. 10mm longer than a Top Fuel
Chainstays are shorter than all of the above. That's a good thing in my mind
Wheelbase is in the shorter end of modern 'normal'. So it won't feel like too much of a tank
BB drop is the same as a Spark

It's "right" if your point of reference is this Orbea bike that was mentioned and a bunch of other random bike models. The problem is the seat tube is really too long for this length of reach and ETT.  Maybe Orbea had a reason to do this, but spcycle could clearly have thought it through better and shrunk the seat tubes down for at least the small and medium sizes where standover for 29" frames is nearly always an issue for shorter riders.

If spcycle's only goal was just to clone what was already on the market, then that's their choice.   But I would hope to think they are more creative than that.

Yes, we have completed 3D printing and mold development. So the geometric parameters will not change. thank you

Didn't you literally ask for suggestions on the mold in the original post? 

Anyone else running this frame?
Seems like the best value chinese carbon frame at the moment - $1150 AUD delivered off aliexpress.

Can a 180mm dropper be used on a large frame?

The seat tube is interrupted by the shock.  You might be able to fit a 180mm if you are long legged.  My son has a 150mm on his and can probably fit a 170mm.