remounting a koni omega 58 mm lens

Is there a copal/other brand that I can use

The cells are direct fits in a Compur/Copal/Seiko #0 shutter. In K-O mount they're in a Copal #0 modified to be fired from the body and cocked by the body.

They will not fit in a press (self-cocking) shutter, the inner element of the rear cell will hit the diaphragm. Don't waste your money on a press shutter, get a proper cock-and-shoot shutter.

If you go ahead, you'll need to have the shutter scaled for the lens.

I've done all this with a Koni/Rapid Omega 60/5.6. Wanted a 58, but a 60 turned up at an amazing price.

The 60 just covers 2x3, absolutely won't do for 6x12. I doubt the 58 has more coverage. It doesn't have to and like the 60 it has a relatively small last element.

Thanks. I was under the assumption that the 58 and 60 were the same lens.

They are absolutely positively not the same lens. The 60 is an older design, has the f/8 Super Angulon layout (six elements in four groups). The 58 is a newer design, has the f/5.6 Super Angulon layout (eight elements in four groups).

See http://www.rangefinderforum.com/forums/showthread.php?t=63826