For some reason all of my girlfriend's bath products have wide rounded caps, and I was tired of knocking them over when propped up in the shower caddy so I made this to fit a few different sizes of the bottles.
Print on the material you can get the best tolerances with. I did one ABS and one PLA and both have held up equally well over the last couple of months. The trays should be printed vertically with supports for little connecting rods, these also are slightly angled to try to help offset some of the weight of the bottle so it won't tip forward, and need to be printed in a higher resolution (or cleaned up post print) so they slide along their track.
Here are the suction cups I used and outside of a few that got bent during shipping, these have been sticking to the wall for about 6 weeks straight now.