I've looked at many commercially available and DIY spice rack plans, and they all seem to be made for the standard 4.5 inches tall by 1.75-inch diameter spice bottles from the grocery store. This design is shallow enough that the bottles don't get lost in the dark, like our current cabinet that is stuffed to the gills. This model could also be used to store canned goods. I might make one or more for that eventually.
Unfortunately, most of our spices are different sizes, most larger. I measure some of ours, and they are up to 6.5 inches tall. Spices should be arranged by type, not size, so I designed this rack to hold bottles up to 7 inches tall. If I change my mind, I can remove the shelf supports and move them. They are currently fastened with small nails that aren't hammered all the way in until I get my wife's final approval.
This pallet was originally wider with four prime ribs. I removed one rib to make it look more like a small pallet and not be too overwhelming in space it is mounted in. Now that it's up, I may go back and make it with all four ribs for more space. All the parts were from pallet pieces, cut on a table saw. It has no finish on it. I might stain it later, but it looks pretty good now. I did remove a few splinters that were hanging off, but not many. It is fastened to the wood wall studs with four three-inch deck screws.