An orbital will easily keep up with 2 putting 4 layers on
Will just keep up putting 6 layers on
And give one baler a good hour head start putting 8 layers on or you will be doing a lot of waiting around.
4 layers will do 90-110 per hour
6 layers will do 70-85 per hour
8 layers will do 60-73 per hour
Depending on conditions tractor oil flow and how quickly you can change the wrap
To get the top end of these totals you need to have a bale waiting on the lifter at all times and change the wrap like it’s a race but will do it.