That sounds good. It will need a bit of thought about pulling targets up otherwise there may be a tendency to leave them down in order to exit. Some targets can be awkward to reset from the sitting position and need a FAFF standing - or there will be a lot more whistles!!
When does clock start? bum on bag? First one of (say) 3 has a slight disadvantage in that the others can ponder the lane, wind, etc while #1 is shooting.
Definitely needs some experimentation and trials.