Overall I'm in near total agreement with Richard that a Side mount CCR is not what you want. Not now. Maybe not ever.
It's not ideal for offshore. I can make a side mount CCR work in that role, but it's not ideal, and we do very few deep offshore dives anyway. If it was my primary interest, I would not have went the side mount CCR route at all.
Marci and I converted from OC side mount to CCR side mount and skipped the back mount CCR since it didn't make much sense for us to move back to a back mount configuration after 7 or 8 years of side mount OC diving, given that we intended to use the CCR in the same small passage cave environment where side mount made sense. And we still dialed are cave diving way back in terms of penetration and difficulty for 100 hours or so after our CCR class.
If we had not had extensive SM experience we would have went back mount CCR first, got a couple hundred our of time in back mount CCR and then converted to side mount CCR In that regard, unless you have a lot of side mount experience, I doubt you'd be able to find an instructor who would cross you over all the way from back mount OC to side mount CCR.
In your case, unless you are going to do actual side mount cave diving, rather than cave diving in a side mount configuration, you probably should not, and would not want to go with a side mount CCR.