There is no 9999 limitation. Generally, the job distributor will format names to have 4 digits, because that’s the style we’re used to. If you pass nstruct > 9999, it starts adding digits as necessary. I’ve done one with 7 digits with no problems. It generally formats the names to have the same number of characters throughout. Example:
nstruct 1
start_0001
nstruct 200
start_0001 (no change)
nstruct 9999
start_0001 (no change)
nstruct 10000
start_00001 (more digits, even from start)
There is a hard upper limit to nstruct, probably whatever the integer limit is on your hardware. Way more than you’ll need, anyway…