Your machine is a bit newer than mine, so things might be different. In post 6, is that a washer behind the top right screw? My screw sits flush to the head.
In post 8, the gap between the head and the rail seems wider than mine. Can't get my caliper in there, but sticking a normal round tooth pick in the closest space.. it will not go past the taper to the straight portion of the toothpick. .04 on my caliper. The real issue is whether it is tipped away at the top. Whatever the top distance is, make sure the bottom is the same.

Bottom line, call LHR in the AM... the folks there are very knowledgeable!!