I think the 400s are a good bet. There was our last really long-lasting sideways market in 2015/16. I think it will go lower only in the very worst case, if even after a possible fork there are still attacks between both coins.

And I think if we really go bearish now, the first strong support will be likely in the ~950 range (retest of the "ETF low") and if it doesn't hold in 735-800 range. The next one: 4xx, as already said.