Don't know a great deal about the options out there but my thoughts are this:
It is somewhat more than "a few k" difference between doing an IR reval and a 737/320 type rating, especially with CAE who I don't think are the cheapest out there.
In Europe the 320 rating is going to open more doors I think. I don't know about Africa, my initial thoughts would be on how commonly they hire Europeans.
As I said, I don't know the options out there but I doubt that CAE are the cheapest, I know cheapest isn't best but I would suspect they aren't best value for money either if doing it entirely self sponsored.
If you are determined to do a speculative type rating, why not try to get on one of these schemes that might get you a job. Ryanair obviously being the main one, but even the less ideal ones like CAE's flydubai one or I think Aer Arann also doing ATR ratings and add you to a list of people they might employ if they ever need to.