Yeah, the yoke is not the weakest point in this situation. The Apeks yokes are rated to 3500 psi, and the Yoke to DIN converter for filling is rated to 3000 psi (at least the Sherwood ones are).
I would get the standard yoke connection on the first stage, and then just get a DIN converter with it. That way, if you want to use DIN, you can switch out the yoke and install the DIN. If you dont know what I am talking about, then you should speak with your local Aqualung/Apeks dealer, and they can help you out...