Just curious to see if anyone has modelled these? Any tips on Baccus products to suit this? I was thinking of the oxen wagons as the base?

I think that AMC02, the Mesopatmian Battle Car, would give a better look than EQU11.  Of course, you would need to get EQU11 to get the oxen.

Alternatively, you could get PWA13, Settler Wagons.  This would give some variety of wagons which seems to be historical and includes oxen. 

Good luck