mismatched double pups

How big of a difference would running two different pup trailers as a double make? (assuming the heavy one is up front)for example, a drop frame moving van 28' (19.5 tires) and a liftgated straight floor pup on 22.5s? Is the pintle/drawbar height always the same height? What sort of concerns are there fore the converter dolly?

 

We'll be running them out to the pike with 2 tractors and joining them for longer trips when we get that setup going. We do HHG and pups are good for getting into all the f'd up side streets in the area. Instead of one 48' the idea is to load two 28' pups. We use our local single axle day cab for the loads and rent a sleeper truck for the long distance part. We have one dropdeck HHG pup already but the sister to it just came up for sale, but I'd rather get a liftgate dockheight pup for versatility. Just wanted to make sure that'll work before I pass on the matching 2nd HHG pup.

 

the trailer we have now would be the front trailer, it's 13'6" so I'd aim for another 13'6 pup for behind. I won't be hauling them together in the city, more like bring one to downtown Boston, load it, then swap in the other, load it, then join them out near the highway and drive to San Francisco. That's the plan anyway.