Since you are using e targets... there will be no pit changes... except for a major maintenance or backing swap.
Why not allow a shooter to shoot BOTH bolt and semi if they want to?
That would double the rd count shot... and it would be a hoot.
Or just increase the relays for more shooting per day. With the fast 1 1/2 min relay, you can cycle through 3 shooters in about 15 mins... so the entire field could be done in about 1 hour.
The next event would be done in about 1.5 hours.
Now what do you do the rest of the day?
If everyone has a reader to see the target, the need for a spotter becomes redundant. There is nothing to spot and would actually slow down the shooter.
If you put them in groups of 4 - 2 shooters per target, you would cycle even more shooters through fast.... one shoot, one score. the other pair sets up or is set up. By the time they are done, the first scorer can be set up as the next shooter. Infiltrate so the line doesn't stop shooting. The time limit would be started by the scorer and a stop watch.
With only 3 targets, you have no problems spacing out gear/mats and shooters. Infiltrating new shooters would be super easy and fast.
You can run ALOT of shooters through this way.
Jerry