I wouldn't do it to a sheath I make for someone. If I'm to assume your profile pic is your work. Then I would also assume we do things very similar normally. I usually do it the slow way though, and I do everything with hand tools. I usually form it by hand like you were describing when I make something nice.
One day I was thinking of grabbing up one of those hand crank machines
Weaver sells, because sometimes saddle stitching just takes longer than I'd like. I'd also like a way to make stuff if the power grid ever goes down. I was just saying there are ways to use the sealer without it being "way too tight" if you're just throwing something together in a hurry. It can be made to look good too if you care enough to to do it.