I would take the tire off, or at least deflate, before truing.

You don't need a truing stand - just put a zip-tie around one of your seat stays and use it as a gauge.

Tighten the non-drive side by 1/4 turn on each spoke, then evaluate the centeredness. If it is close enough then do no more. If you want it to move a bit more then loosen DS spokes 1/4 turn. Evaluate again, then repeat the process. To get the wheel to move 1.5mm you shouldn't have to do this procedure (tightening + loosening) more than twice.

Generally speaking, you want the total amount of tension in all spokes to remain roughly the same, which is why you try to loosen spokes whenever tightening spokes. In my experience, though, most wheels can handle a slight increase in total tension, but many cannot handle a decrease, hence my advice to try tightening NDS spokes without loosening any when you start.