The game will have one single day with no lynch mechanism.
Everybody will be a 1-shot dayvig.
If everybody alive as used their dayvig ability and there are more than two players left, they'll gain another shot.
The game ends when there are two players left.
Town wins if all scum were shot.
Mafia wins if they can kill town by themselves (example 4:2 with both mafia members with a 1-shot dayvig left, even if there's another town member with a 1-shot left).
Choose a player to shoot first. Let that player choose a target (if the target is known and is Mafia, they'll use their kill first). Choose another player to shoot the previous shooter. Repeat. EV is close to Nightless (or the same?) - not wildly imbalanced, but townsided and might as well be Nightless.
It's not identical to Nightless. If the player you choose to shoot the previous shooter is scum, then they may well just violate the plan and shoot the wrong person because they're doomed; they'll most likely shoot a townie who hasn't used their shot yet (to reduce the number of shots left in play). Someone will then have to waste their shot to clean up the known scum, and this basically leaves you with two popcorn-shooting chains, rather than just one, messing up the EV calculations. I believe the setup is somewhere scumsided of nightless, unless there's a way for town to break it (and I can't see one).
Also, this is a Bad/Worse Idea variant. I forget the naming conventions for the various Bad Idea setups but suspect that this particular one has a name already. They're normally considered the most reasonable way to run very large games, but players tend not to take them seriously in practice, which would lead to the setup becoming substantially more scumsided due to townies messing around rather than scumhunting.