Hercules Stands HCGSP-38WB+

Hercules Stands are quite good, coming in a super simple package containing a wall holder, arms width reductors for guitars and a pair of dowels for installation.

Please do yourself a favor and buy a pair of regular dowels, you're just adding one euro of expenses, most likely.

Wall holders look sturdy enough, using them for both 4 and 5 string basses, weighing around 5-something KGs, and as expected they didn't move an hair, no rattles, the locking system works smoothly.

Load Capacity is 7 KGs, which is a little below the line I would've drawn, and put me in a situation where I want to sit my basses back on their holders slowly, with care, and not try to see if those ~1.8 kgs left as "headroom" are enough.

It's hard to do better with 17 euros.