An interesting thread! I aint no shellac guru, but I'll chime in with some mostly unfounded opinions. I've found trying to predict what color they'll come out is like betting on the weather four weeks out. After staring at that picture of your saddle, I would, if it were me, try a few flakes of Garnet shellac, mixed with twice a few flakes of orange shellac, over white or tan Newbaum's. I say a "few" flakes" 'cause you don't want to mix too much. Ask me how I know. Buying shellac flakes in small quantities can be a challenge though, unless you want to get skinned at VO. I only have orange flakes right now, but if you don't have any and would like a small sample, send me a PM. I've enjoyed experimenting with bar tape and shellac, but it's always a crap shoot when trying to match a certain color, I've found.