MichaelMc
Working toward Cenotes
The OP is curious about the feasibility of sidemount being the first setup they buy gear for, after a month of diving it in Thailand.What about backmount without a manifold? Independent back doubles... ??????
They could have many reasons for wanting sidemount. Redundancy might be one of them, and yes backmount independent or manifold doubles are another solution to redundancy. They also might just think they look cool, or like the flexibility in the water or in renting tanks. Lots of possible reasons.
One disadvantage of sidemount is some people just do not get wanting to do it, for anything short of confined no-mount passage dives. Or, that boats some dive from are fine with it. Pros and cons.
The point about maybe eventually getting a bp/w is good to keep in mind. Once you've bought BC, regs, suit, fins, lights, strobe, DSMB, etc. the extra cost of a backplate/wing/harness to sometimes do back mount may not be that much. I'm not saying they need to. But its not like they can never dive anything but sidemount.
Depends on the dive environment at home, but seems fine generally.
ETA: Yeah, I'd work at figuring out your eventual rig in Thailand and diving and tuning it there. It will take adjusting for home, but less this way. Unless you've got good sidemount instructors or fellow sidemount divers at home.