We're rehearsing in various rooms of a church (classrooms, choir room, worship center, fellowship hall) depending on which room we can get for each rehearsal. The performance venue hasn't been entirely set yet, but we're hoping it will be in a local high school auditorium, where one of the Board members teaches. Specific venue negotiations are ongoing. If we get that facility, I am pretty sure I'll be able to see the venue and be able to get comfortable with it.
Yes, I had already thought to tape out dimensions of the final venue at our rehearsal space. I'll bet that gets old real quick, doesn't it? We'll have to tear down and clear all rehearsal material after each rehearsal.