Also it might be the picture, but there's no copper around the feed screw, right?

Oh there was, I was just seeing was the gap was to get into into compression that way.  Didn't put it together with that now.

Instructions would be more clear if you just stated that the nylon bushing is supposed to contact the flange in operation and the compression is the material to that interface.

I think I understand now, the goal there is to make sure the boards are far enough apart that the bearing will be in compression before the screw bottoms out on the socket.  So then I guess the point is to leave some slop in there and then it will all stay in compression when the plastic pushing on it.

I will just leave the heater as is.

Bingo! I will re-word the next revision to better reflect how you just described it.

The socket on the motor isn't supposed to touch the nylon. Not sure where that idea came from.

You should be able to slide the feed screw back and forth 2-3cm. Slide it so that the thrust bearing is compressed. Proceed with assembly.

As mentioned in the instructions, if the heating band says "AccelerationLab" on it, then it is a slightly smaller size, meant for the next design revision. We had to send some of them with the v1.2 units. If you get a longer screw it will work fine, though as you said it is probably not needed.

Well step 22 stated: "Line up the main support on the base, slide the feedscrew into the coupling, ensuring the thrust bearing is compressed, then attach the white angle brackets to the base."

I think I understand now, the goal there is to make sure the boards are far enough apart that the bearing will be in compression before the screw bottoms out on the socket.  So then I guess the point is to leave some slop in there and then it will all stay in compression when the plastic pushing on it.

I will just leave the heater as is.

You should be able to slide the feed screw back and forth 2-3cm. Slide it so that the thrust bearing is compressed. Proceed with assembly.

As mentioned in the instructions, if the heating band says "AccelerationLab" on it, then it is a slightly smaller size, meant for the next design revision. We had to send some of them with the v1.2 units. If you get a longer screw it will work fine, though as you said it is probably not needed.

The instructions state to place the shaft collar all the way up the feed screw.  I moved it up the screw to the point where the screw got bigger so it was as close as possible to the screw.  When I got to step 22 in the instructions, I could not get the bearing into compression and in fact its not really even close.  The socket on the motor is quite a bit off from the piece of nylon.  This could be fixed by taking it back apart and moving that shaft collar down closer to the base, but I don't know if that is the correct solution.

The second is that the heater band provided is quite a bit smaller than the coupler.  I stretched it out to get it over, but there is quite a bit of gap left.  Once its on there the clamp can also be streched over, but doesn't seem possible to get a screw in there.   I'm not sure there is much need for the clamp if the heater band is so stretched out anyways.  I do have some heat wrap tape to improve the efficiency due to any loss from less contact.