Agree with Bram, maybe start the PLO at 1pm and make it a one dayer? Then anyone wanting to play it can play day 1a and PLO on 1b...... Also leave an extended late reg period which would allow 1b bustouts to hop into the PLO and try to get out of the 1k hole.....
Appreciate they're might not be room in the cardroom at 1pm tho, with a big 1b field expected.