I was intending to have 3 day boot limits. But 1d10h with bank is also an interesting proposition. I'll have to think a bit more on what the appropriate bank time would be.
I personally would vote for 3d instead of 1d10h with bank, but in general I think banking is an under-utilised feature on WL, and when it is used it is used badly (mostly in FFA RT games which forces people to needlessly wait for one guy who just left without surrendering).
At the same time if used with multi-day, it can be a more useful and interesting option, forcing faster play in general (which is what you want for the ladder it seems), but allowing to take an exception here or there. Think about different options such as 1d initial bank + 5% of time left, which would encourage people to play faster if they want to take a few days off later without taking a vacation