Chipperman,
Here nobody uses loaded tires. Even for plowing. Maybe rear wheels weights, sometimes.
Good hydraulic system can add enough load to rear axle for plowing.
As we have narrow field roads, sometimes looking like a canyons, in 99% of cases 1410mm (55 1/2 in) rear wheels track is used (factory settings).
I know that UTB (Landtrac) can't be compared to x21/41 series, but we haven't a lot of this Zetor models here.
Price difference is too big for what they offer, so people buy more x20/40 series. I don't know how tractors are equipped there, but here x21/41 just have 540rpm PTO, no reverser, no A/C.
Most popular UTB model is Universal 643DTC, equipped with insulated cab and heating, like Zetor models. Cab is narrower and about 10-12" lower than on Zetor models.
Most popular Zetor models are 4320/40 and 6340.
Personally I prefer lower tractors, like NH TN(D) series. They have lower positioned seat, and are more pleasant for ride on bumpy terrain (because of lower left-to-right seat moving).
I like cab design of new x21/41 Zetor, similar to Fortterra series.
Anyway, Zetor is good choice, I think, as are many other brands, too.
Just look carefully for all advantages and disadvantages, and try it before purchase.