Pick the truck, mount the crates, fill the slots. The whole logistics run priced and weighed before anyone spawns it in.
A hauling run either pays for itself or it does not, and the difference is usually one crate. Pick the vehicle, mount what you plan to carry, and the manifest tells you what fits, what it weighs and what it costs before you drive anywhere.
Trunk class decides which crates and pallets a vehicle accepts, so the biggest truck is not always the right answer for a given load.
Work backwards from what you are hauling. Price the load first, then find the cheapest vehicle whose trunk takes it. A run that needs an expensive vehicle to carry a cheap load is a run that loses money the moment anyone shoots at you.
Fuel and distance matter as much as capacity. Two short runs in a cheap truck often beat one long run in something you cannot afford to abandon.
It depends on the vehicle's trunk class, which decides both how many slots it has and which crates and pallets fit them. Pick the vehicle in the planner and it shows the grid filling as you mount things.
The cheapest one whose trunk takes the load you are actually carrying. Capacity you do not use is money you spent for nothing, and an expensive vehicle turns a lost run into a much worse loss.
Each has its own slot count and health, and the vehicle's trunk class decides which of them it accepts. The planner only offers combinations that actually fit.