The smaller version, the one with 5' tall rear wheels needed 4 horses or 2 oxen. The bigger ones needed between 6 to 8 horses (or more) or 4 to 6 oxen (or more).
I got to ride in a restored one back in 1976 and it required a ladder to get in it. The rear wheels were about 8' tall. It was on a cross country trek and was being pulled by 6 Clydesdales with 6 others in reserve.
I recently participated in a cattle drive commemorating the 150th anniversary of the Chisholm trail. There were 10 wagons involved and 2 of those were "prairie schooners". Those are big wagons but could fit inside a Conastoga wagon.
The 1st pic gives an idea how big the horses would of been. I can't remember the name of the breed but these are a special breed used by mounted nights and for hauling aftwards. They pulled one of the schooners.
The last ones are just general pics from the trail.