Roodkpvoske

I found the easiest way to do this is to hold the nut in place with a small magnet and then fastening the screw a few turns, so you can pull it in it's place.

I disagree with this, don't leave your belts any longer! I did so, thinking it would be easily adjusted afterwards, but if the belt grabber reaches the end of the EVA3 assembly during tensioning it will get very stuck (as in the belt ripped out and it still didn't budge stuck). Prevent this by cutting the belts short enough beforehand.

Be VERY carefull with this part; I got the printed parts set and some tolerances are too lose (nuts keep dropping out and one is just shredding plastic as it turns around freely) and others were so tight the screw went in instead of pulling the nut in. Make sure to place the part flat down when you have to insert nuts so they can't rotate/tilt and get stuck. The safest way to get them straight in is to use a bolt to pull them in, otherwise you risk threading the bolts in wrong and then you are screwed.