are intermediate shutter speeds possible with copal shutters

[E. von Hoegh]

For shutters that can do it, you would have to test fairly carefully right before making the exposure, and then it wouldn't usually apply to the top or the bottom speeds. After all, how accurate is your average ancient Ilex/Alphax/Betax shutter anyway on a good day? I wouldn't count on better than +/- 1/3 stop on the marked settings to begin with. Well-maintained dial-set Compound shutters, though, might be a bit more reliable than one would expect.

Yes, a Compound in good condition is very accurate.

[TheDeardorffGuy]

My old shutters are dead nuts perfect on up to their top speed. Then divide by half.