I think I will have trouble getting to the O2 off in case of a solenoid jam open on the O2 injector, especially with a dry suit. This will not be a problem on the dil. side and i think It might make hose lay out a bit easier.
It,s nice to know a few guys out there use this setup and do not seem to have had any problems.
I guesss I could route the O2 to the inject input from a take off with valve on the manual inject counterlung that way I would have good manual control if needed.

Anyway thanks for the reply, much appreciated. abc