[fastd]

imo, I don't think that you should be dissuaded from owning a Cobra for lack of wrenching skills. You've obviously owned a stable of cars in the past so you know what you are getting into. I've owned my Cobra for 11 years and since it's not driven much more than 1,000-2000 miles per year, mechanically, it hasn't been that demanding. If you have a good shop that you trust and you have the money to pay out, you will be fine.
To address a question you had in your OP, I've never had anything close to an overheating issue - most Cobras have huge radiators and electric fans - they just don't overheat like cars from the 60s and 70s.

Generally speaking, I think buying a used Cobra is a good idea but one with a 5-6 speed and with EFI seems like what you would want. I'm a big fan of the 351 in these Cobras as a solid middle ground between small and big block. I've seen used Cobras with Coyotes and EFI is getting more popular. Prices are coming down it seems; they market is coming to you. Keep going!