Haven’t done that, was wondering how I would remove the bushings after putting them in to check the string action, then came across this video
For the purposes of test-fitting, checking neck alignment or angle, you don't need to install the bushings. You can simply wrap masking tape around the threads of the posts to press-fit them into the holes. It's just needs to be tight enough that they don't drop out when your moving the position of the guitar. They will be centred well enough to give an accurate assessment.

I have some 8mm ID clear vinyl tubing that works perfectly for doing this also.