C41 Onje shot developer

I have been using Tetanol tablets to make one shot dev for 35mm films and it's a bit expensive. I have now changed to MF so I now need to use 4 tablets per film to get to the required 600ml and the cost has doubled.
The Tetanol instructions say that 1 tablet is needed for a 35mm film - presumably in a rotary tank. Anybody any idea what the dev times are for greater dilutions or alternatively a cheaper source of 1 shot dev.
Any help gratefully received.
Jeff

What tank are you using that needs 600ml ? The Patterson needs 500ml to cover one roll of 120. If you're willing to switch tanks how about these:

http://www.jobo-usa.com/products/1500.htm#Technical Specifications

500ml will do two rolls of 120. I don't think these tanks are much if anymore money then the pattersons.

600ml ??!!?? Geez, that tank needs to be thrown in the nearest trash bin! Find a used Jobo CPE or CPA (< $300.00 for the CPE w/ lift). I use the single MF drum for it and it only takes 250ml. I've even run it with 200ml and never had a problem.

I use the 10L Kodak Flexicolor chems. In a "one-shot" mode. Cheap, simple, and lasts me for 3-6 months at a time.

Another idea is putting two films on one reel. I always do this with my MF rolls and never had a problem.