How durable a finish are you wanting? If the answer is "very" it'd be hard to beat a polyurethane, which could be a plus depending on how high the usage on the boxes is. If you don't need an indestructible finish and want something easy to work with, I'd bypass laquer and go for shellac. Cheap, easy to spray, easy to repair, quite durable, if not the level of polyurethane, fast drying, and gorgeous. Best of all, with its solvent being the relatively mild alcohol its a little safer to spray than lacquer.
I'm not dissing lacquer by any means, I'm just more partial to shellac. If you're set on lawyer, deft seems to be a pretty good choice. I haven't used it much, but it seems pretty popular and seems to work well