The holes on the Rpi are to fit an m2.5 bolt through, the screw posts are only used more as a guide for the bolts. When all 4 screws are in, it holds the Pi in place fine with no play or movement IMO. Now you have it together, would you agree? I think maybe a second model just for heat set inserts with no holes in the bottom and just a 3.8mm hole in the screw posts for the insert to go. It's a nice suggestion and I'll aim to add it soon. I can make the screw posts longer but it means the print takes a little longer. What do you think I should do with it? Do you think it would be better with longer screw posts that go all the way to the board?