I thought this was a good test like most everything he does. Yes, the destruction stuff is typically somewhat pointless, but in the case of a jack stand, I think the ultimate strength is actually highly relevant- as opposed to putting 600 lbf on a pair of pliers in a hydraulic press - which no human could possibly do. Keep in mind that he's also going for an entertainment factor.
On a solid rear axle vehicle, I typically put the jack stands under the axle tubes and close to the wheels. The only time I don't do this is if I want the axle to hang down for access above it. I realize that there are always people here who find something to nitpick about in his tests (nitpicking is easier than actually doing), but I was surprised to see this pointed out as objectional- it's perfectly fine. Yes, he put them inboard, but that was for a reason, as pointed out.
As far as tipping, if you tested all the jack stands at the same support height, the one with the widest base in the direction of the applied force will have the highest required force to tip over. This is a simple summation of moments, and second year Statics class in Mechanical Engineering.