Thursdays should be pretty decent once the new store happens since even if MTG players are around, there will still be plenty of room for them, other mini games and 40k.
I plan on switching gears a bit once the WM/H league ends for some 40k. That new CSM codex needs some love.
EDIT:
With limited game time, I find it hard to really divide between the two. Besides, I think people are sick of seeing a stormwall stuffing their armies.