I've never had to replace all the spokes on one side, but I have needed to replace half of them due to a misadjusted derailleur that shifted into the spokes and nicked or snapped them.

Replacing the spokes one at a time worked fine. I just initially tightened them to a fixed number of turns to keep the wheel round and then completed the truing once all the spokes had been replaced. Didn't take very long and worked fine, i.e. the wheel is still in use 50,000 miles later and no more spokes have broken.