ty_in_ND,
1.) I used a small paintbrush, like one of those paintbrushes that come with the water colour kits they make for kids, only I got it at Tandy. I just randomly put brush marks all along the back. I started with light colours and worked my way to dark. First yellow, then green, then blue. By then, it looked pretty terrible. But then I did medium brown, mahogany, and black, and it looked good. I used Fiebings leather dye.
2.) On my all bamboo bows, I always cut off a 1/8" strip and flip it, but I just started doing that on my ipe bows. I don't see what difference it makes whether you use a different 1/8" strip from a different piece of wood or one from the same wood only flipped. i flip them end to end, by the way.