If you do the wall mount, here are some things to remember:
1) Mount into studs only. I used 1x4 wood strips because I knew my placements would not allow this.
2) If mounting near the ceiling, make SURE you mount while allowing enough room to pick the bass UP out of each hanger without contacting the ceiling. This is really easy to mess up! If you go for two rows like I did, this is critical because you'll have to mount the top row pretty high.
3) Make sure the lateral spacing on the top row gives enough room on the bottom row to hang a bass AND the extra width of the tuners between the bodies of the basses in the upper row. Those tuners add 4-6 inches in width, and you don't want the bodies on the top row banging into the tuners on the basses in the bottom row.