The GUE configuration has no logic in terms of CCR diving but has some in terms of trying to morph over ideas from their use of the RB80 and a need to keep to some form of standardised system along the lines of their OC system
GUE did a frankly amazing job of creating a standardised rig for OC diving, but the desire to keep everting in line with the GUEs version of the Hogarthian concept, has lead to some less than ideal solutions
Their CCR rig is the worst of these by far.
I experimented with manifolded 7s on the back with off board 02 for the purpose of diving boats where kitting up was very difficult so having all my bailout on my back helped.
The rig is unwieldy and the equivalent of driving a bus to driving a sports car. The two 3ltrs on the back are far more comfortable to dive.
It also goes against a basic safety concept of CCR diving, which is to keep your bailouts totally independent of driving the CCR its self
Having the valves at the top is also a bit of a step backwards to a time where we all struggled to reach them. On a CCR theres no effort involved as they are by your hips.
Its sad to say but I also feel that GUE had to do something different to make them stand out. They fought against the use of CCR for many years, but in the end had to accept it was the only way forward for trimix diveing. SO I have a nagging suspicion this was a face saving exercise in some ways. Rather than admitting you could just stick a CCR on your back and go diveing they sort of reverted to type and said, OH NO your all doing it wrong you should be doing it like this .
IMG_3392 by markchase8, on Flickr
Having been on a boat with the GUE ccr, it works and Iíve modified mine in the 40-60m range to suit.