You can calculate just how wide a seat will fit with a tape (I forget the number). The specs for most seats can be found with some digging.
Height really depends on your leg length. The OEM seats are pretty low profile to allow for short drivers and you will notice that the highest point of the base is *well* below the transmission hump (several inches). When you look at a lot of installs, you will notice a lot of them are *higher* than the hump, And that's fine if you have the leg to reach the pedals and you are the only one to ever drive the truck.
Also keep in mind that the OEM wheel is at 22"(?) with very limited tilt. So at some point you may end up with the wheel resting on your legs the higher the seat (you can of course run a smaller steering wheel, but at the cost of leverage).
Lastly, and it's more of a personal thing, are the hip bolsters in some seats. While these are great at holding you in the seat when you are bouncing around off-road, they can be annoying to climb over for some people. In sports cars that you slip down into they are a great fit. But in a cab that you already have to climb up into on a regular basis they are an added obstacle to navigate and lift yourself in and out of the higher the bolster
Bottom line, LMTV seat solutions are like office chairs. Go into Office Depot some time and try to find the most comfortable chair. Rarely will two individuals pick the same chair though.
ymmv