Let's say I had a choice between 1x12 for shelves and actually joining two ripped pieces of 1x8. Contrary to the initially appealing, I'm inclined to think that wider lumber tends to warp more than, say 1x6 or 8. So I'm inclined to actually go through the biscuit joining process to prevent warping.
Are my assumptions correct and the resulting approach? Basically, is it better against warping, to have two narrower plates biscuit joined or one wide plate?