Homemade paddle strop question

I am planning to make a paddle strop that I plan to use for pastes. I have access to leather (Tandy) and balsa in the area. I assume that the price difference wouldn't be too dramatic between the materials, but my question is which one is recommended. I've heard good things about balsa with paste, but most of the ones for sale at SRD and Tony Miller have leather. I plan to make at least 2-sided with 1 micron diamond and 0.5 CrOx. Any other suggestions would be appreciated.