I recently bought a Hercules GS523B Guitar Rack for my basses.
It's a well made rack but has, to my mind, an annoyance in that it holds guitars canted at an angle.
With basses (longer necks) the heads project beyond the stand's footprint and make it impossible to place it against the wall.
Some though later and I devised a useful mod.
The lower, rear padded crossbar can be mounted in two positions (there are two sets of screw holes 30mm apart). I drilled a third (6mm) hole, 40mm further back and mounted the crossbar there.
The basses now sit much more upright. Another small gain can be gotten by moving the end stops for the sliding mech to the higher set of holes.
The rack now sits (almost) up against the wall and the basses are more upright. Stability is maybe improved too.
See attached crappy pic...