I don't think you have to go to a specific outfitter or PH for a handgun hunt, although maybe some PH's wouldn't be interested.
I'd say it makes sense to decide what country you want to hunt in and then look for the best outfitters in that country.
I've done two rifle hunts with Mokore Safaris, one in Zimbabwe and one in Mozambique and they are top notch. But there are many other good choices.
