Start at 0.7 and work up to .96a. Anything above 0.7v you should have a fan pointed at the driver heat sinks.
Not sure why you divided by 2 from the .96 I think that is in there from the pololu video for the a49 drivers. Steppers don’t need to be super exact. You can under and overpower them safely. The drivers can easily over power them so just keep upping the voltage until the steppers are warm to the touch after some use. Make sure they don’t get hot enough to soften the pla mounts.
Just to give you an idea. ours are shipped at .7 and work from .6 to 1v