I always hate the fact that such racks have a lot of dead space to them. Instead, I bought a couple of old cd racks for next to nothing took out most of the shelves to leave two sections, and hey presto I have a compact means of storing lots of rods. The only addition was a couple of bits of dowling either side which are about 0.5" long which hold a flexible piece of plastic pipe to keep everything in place. Total cost about £20!
Recently, I adapted it for long two piece rods by taking out the middle shelf but the principle still applies.
These could even be mounted horizontally on a garage wall if wanted depending on what space was available.
That’s why I made a rod holder with loads of spaces for more rods so when another one gets delivered the answer to the wife is that I need to make the best use of the rod holder. It looks ugly with empty holes.