I want to have most of my meetings 1) on Mondays and Thursdays, not other days of the week, and 2) right before/after other existing meetings, but still show availability at other times.

The way to implement 1) is using Ranked Schedules.

The way to implement 2) is using an Optimized Schedule, which is mutually exclusive with Ranked Schedules. I want to be meeting slots to be marked as "Best" only if they're right before/after another meeting.