I seal the backs just in case, On my last batch I split off most of the heartwood and had some stave warping, After talking to a guy who only uses mostly hickory who leaves his debarked trunk in a halves for 6 months before he splits out staves and has little or no warping I think I probably should have left the heartwood on for a while before I made bow blanks.
Here are my splits, some with the heartwood knocked off. Part of the reason I removed the heartwood was these splits were very heavy and I had to drag most of them off a high ridge, they were too heavy to carry.