Much less than a full can, and I don’t notice any difference in weight. Many years ago I made balsa wood airplane models with paper stretched, wetted, dried, and then painted, but lightly. 1950s we’re talking about, and I have some old model kits from my father’s estate, but they’re very old and dried out, I think.
The P-32D looks good. How well the finish will stand up I have no idea. I’m neither optimistic nor pessimistic. If this doesn’t hold up, it won’t be because I didn’t take sufficient care, and it will indicate that a different process is required. If the finish holds up, I’d like to add a Yamaha tuning fork logo, which is familiar mainly from Yamaha motorcycles.