Myself, I have never done a B-Butt. I have done many picnics, and have an 11 pounder calling my name for a Friday-Saturday smoke. I have done both skin on/off. If you like the extra bark, cut most of it off before you smoke it. If smoking on the lower rack, you may be better off leaving the skin on ifin you use sand in the pan.
There is a very large vein in the picnic. I'm trying to think if you would only see it after you remove the skin during your pre-smoke rituals, or if it's on the non skin side.
I love picnics. I also inject them with various "potions" I have created. Most of them start with apple juice, and then who know what else lol.
Most of the time, I can find them on sale for .99 a #, but did get the past 2 for .89/pound. I use hickory, squite, or cherry.
And I have never had a "hammy" tasting picnic either.