I thought it would be a bit tricky getting times right without a shutter. I have planned for some outdoor/daytime shooting. How would you go about doing that anyway? Lens cap? and won't that effect the sharpness of the image even on a longer exposure time? (The removal and replacement of the cap that is)
You can accurately time down to 1/16 or so quite easily, if you are musically inclined
But 1/2 sec to long exposures are trivial. Here's what I do. I took an old darkslide and put on some of that stick-on black felt material from a crafts store. I take off the lens cap (with the film darkslide still in place covering the film). Then I cover the lens with my felt cap, withdraw the film darkslide, and release pressure on the felt cap so that it is barely contacting the lens... then the camera won't recoil when I withdraw it. Then I count up my rhythm for a few seconds and then take the shot.
The trick is to use the felt's ability to block the light without applying strong pressure to the lens- that way you can withdraw it without recoil. Whether you do this single-slide felt thing or the two-slide thing, you have to prevent recoil.
You could also use a big, black hat if you feel so inclined. Or a cape. Whatever suits your wardrobe.
I have been using this tactic with all manner of shutterless lenses. No big deal at all. The quickest exposure I feel confident with is 1/8 or so. But you shouldn't get too bent out of shape over a stop or two, if you're shooting b&w print film. If you're shooting to paper then you
really don't need a shutter at all. You're looking at 2 sec exposures at least and, anyway, you will be developing by inspection. For that matter, why not shoot to [slow] ortho film and you can also develop by inspection. Who cares if the exposure is off by a few stops.
Another thing you can do is rig an enlarging lens to a press shutter, sometimes they are inexpensive. Actually now that I think of it, I have such a shutter for the tominon, the pair were off an MP-4 camera. It claims speeds to 1/125.