I think the phillips is more for aesthetics, jewelry pc.My opinion of small screws.....Allen can be just as bad as phillips when you have to use a small allen wrench. Hex head may be a better choice when the bolt/screw is small.
With the proper bit and some never seize shouldn't have happened in the first place.
Gotta be close to if not a 5/16 bolt. Everything stock I ordered was wrong, gotta measure.
Quick can't I rant moment.
Remember when every hardware store had hardware??? Like anything you could possibly need,
nuts bolts and washers.