I usually use my Distagon 50 mm and I haven't spent much time in pinhole photography. There was long time ago but something I can share. I used a tripod and after I got the diaphragm of my pinhole the process was the same as photography with lens.
Yes, exposure always was more than one second.. There wasn't air to move the leafs.
That's really nice - and very similar to what I did when I first got my Mamiya RB67 body and didn't have lenses yet. Very, very nice pictures you're making there.
I bought a pinhole body cap for my RB67 and it works great. I take the film back and pinhole dap off to look through the camera to line up the shot. Been awhile since I used it but I think after testing I expose at 4 or maybe five seconds on a sunny sixteen time of day and double the time for every second under that.