Why do we argue this?
Singles wing for singles.
Doubles wing for doubles.
Doubles are NOT hard to adjust to, I did it starting around dive #12 and haven't looked back. And I am nothing special in the water.
Golem wings are the toughest wings on the American market that I have seen, and I've seen nearly all of them. The shapes (on doubles) aren't optimal though. I do like and recommend their singles wing, however.
If someone lacks the skills to manage their drysuit and BC and can only handle one, fine. Other people apparently manage the task load without issue. I would be SERIOUSLY nervous about diving with that person though as they could certainly not keep track of a buddy, if they can't manage their own BC.
How far can you go on a single? I'd say 80-100ft. Below that, it's just not worth it in terms of time spent, and safety. Put doubles on, and leave the pony bottle alone.
In terms of getting into doubles and needing two sets of regs, etc. If you get into tech diving, this may be one of the cheapest purchases you make. Each of my 3 wings has cost me more than my regs. And I'll be adding a few more reg sets next year, along with 2-3 new sets of tanks. It's just the way it goes. Bite the bullet and do this right from the beginning...