Man, thats a nice figure. I'd recommend just going straight with the red dye cos the veneer is pretty thin so sanding back has potential to sand through and spalt is already pretty dark so itll come through nicely. You can do either way, but its more that spray on finishes are usually done with the neck attached but wipe on oil ones arent because the pieces need to be individually done and its a little easier to get to the curves without a neck to bang against.