Much too early to predict my action without knowing the structure of the split, but at the very least I believe my priority would be Thacker Pass (Lithium Nevada presumably?). I expect I would split my resources between Thacker Pass and the Argentina group (Minera Exar presumably?). Now I'd have two holdings that I'd trade as the situation dictates.
I'll be interested to see in the longer term if Lithium Nevada grows within the US and Canada. We already know they're scouring the continent for opportunities. There are several projects far enough behind TP to potentially make sense as growth opportunties. My personal favorites are CYP and ETMC.
Exciting times ahead.