Well, that's certainly the way I would be going, CCR first, the deep.
I already dive CC, though only with air diluent (= nitrox).
Never had any reason to dive He mixes as most all SoCal diving is within rec depth.
Doubles were never an option, just too damn heavy.
If I dive doubles they're 13 to 19 cf in size and have a CCR in between.
Might go to two 30s with a pSCR in between, but that's it.
The advantages as I see them:
I do most all my diving CC, so I won't have to relearn everything at a later point.
Higher proficiency by the I would do dives requiring He mixes.
Less money spend on gear buying it once, much less on expensive He.
Easier to go from rec depth to extended range once, and on CC, rather than twice,
having to go back from OC deep diving to rec limits when switching.
Don't see any disadvantages in my situation, to be honest.
Am sure someone else will, though.
As far as SCRs for extended range diving are concerned, you want to go with a pSCR.
In the US the RB80 is the only choice, which requires GUE training. Lots of it.
DIR-F, Tech-1 and Tech-2 are pre-requisites.
In Mexico you can get IANTD training on the RB100 Halocline from Germany.
In Germany you can also get IANTD for the Habanero and PSA/E for the RON.
The cmf-SCRs like the Drägers aren't well suited for He mixes.
It's being done, but I certainly wouldn't choose them.
CCR there a plenty of options, with several agencies usually supporting each unit.
