Last time I used grapevine, but it provided too pungent a smoke. I think I'll try cherry this time. I basically treat them like brisket. The one thing I learned is that corned beef gets even saltier when it shrinks through smoking.
I haven't tried it this way, but it might even be good to poach it before smoking for an hour or two, then rub it with pepper and corriander (no salt), chill it and smoke it to finish the cooking process. And since you want to thinly slice it, it doesn't need to be totally cooked to fall-apart level. Probably 180 would do. Of course, this is all speculation!