If he splits it into 2x10 votes, each of these votes is worth only half. (Yes it is still worth a lot, but only worth half than what it'd be if he hadn't split it)

He splits it in 3, and he will have exactly the same amount of vests to vote in proportion to everyone else exactly like before, because his stake did not grow or shrink in proportion to everyone else, so yes he will split it and yes it will still have the extact same % of mv over the top 30 as before.