There is no “right or wrong” here.
Let's just start. The Crafty 400 has 16 inch wheels mounted. The Crafty 500 and 600, on the other hand, have 20-inch wheels. Basically, of course; the larger the wheel, the smoother the running behavior. But of course aesthetics also play a role for us. That's why we made this pre-selection. Of course, every wheel fits every trailer and can be exchanged at will.
The type of tires is much more important. If you are planning a long tour over asphalt, choose a narrower coat with less running resistance. If you drive a lot in the countryside and sometimes "cross field in", then a slightly wider and coarser profile certainly makes more sense.
What you should pay attention to is the right air pressure for the load. A bulging tire pumped up to a maximum (e.g. 4-5 bar) has a lower running resistance but also hardly any dampening effect on bumps or bumps. A "half-full" tire (eg 2-3 bar) will dampen significantly better, but will have slightly more rolling resistance.
" Try makes wise" - and that's how it is. Just touch it.