I go around to the lumber yards and get dunnage boards .These are the spacers they use to ship bundles of 2 by 4's etc .Freebies because they toss them out any ways .Then I rip them to size on my table saw and use these for stickers .
Might sound thin to some but 3/4" by 3/4" has worked perfectly for me and being kiln dried pine or PNW fir I have no problem with staining .The dunnage is 4 feet long so they work perfectly .