You will have to make these decisions for yourself based on your personal ethics. Your PH will ask you if you mind shooting from the truck and if not, tell them if you prefer not to. I can tell you, if you have a warthog on your list, you will have a hell of a time finding one NOT sitting by a pan/watering hole. Ground stalking warthogs is an effort in futility most times. The only animal I shot from a truck was over water as well and was...a warthog. Granted, we had been sitting there with the engine off for 2 hours.
With that being said, usually, you probably will not get a ton of truck shooting opportunities in Limpopo. It's very thick. Your opportunity to hunt from a truck will be very quick. Most of the animals will freeze for maybe 3-4 seconds before they trot off into the bush. That's 3-4 seconds for you to realize what you're seeing, to process your PH's go ahead, and then to actually line the animal up.
Watering holes are a nice break, IMO. After tons of driving around, stalking, etc. it's nice to sit and just see some cool stuff. You might not get to see some animals driving around and stalking. You also don't have to shoot anything either. We spent lunchtime at pans most days and it was awesome just to see the variety of stuff come in.
Here is the shot I took on my pig. We spent 2 days looking for a male. Settled on an old female "cull", of sorts. I had to shoot behind the rump of one cow, over the head of the one in the foreground, in front of one other, and maybe 5 minutes after taking this pic. Not an easy shot to say the least. I confessed to the PH I had concerns about accidentally hitting his cows as it was his land. In one of the best compliments anyone has ever paid me he said "I've seen you shoot, I'm not worried." I still was but in the end it worked out.
Red dot is where the pig was shot.
View attachment 594846