Hello @Eclsnowman and all 
For a better alignment, a single bronze bushing is not better than two Press-Fit bronze ?
Two Press-fit Bronze bushing reduce the constraints ?
I live in France, and the cost of shipping for press-fit bushing is too expensive. I do not find it in Europe or in China. I think to replace them with standard bushing bronze…
Thank you
The two pressfit allows for a wide contact length, with a low contact surface area. It is ideal but others have tried other solutions. For example walter originally tried these (thought he eventually came back to the self alignment type I believe).
He eventually used 10mm long bushings in a ninjaflex sleeve on the central carriage, and 30mm long ones on the side carriages:
