I had a fantastic experience with Regent and cant speak highly enough of them. Ok they only did some work on my wagon, work that should have been done by the builder
but they didnt rip me off, did jobs I didnt ask them to do at no extra charge and the wagons I seen in there in build looked very good. If I knew my horse would travel in a 3,5t box I would buy one off them JM65 bought one off them and loves it. Id love to know Sulas experience, I hope it wasnt bad.
Sorry for gushing but you to answer your question you wouldnt be able to carry two large horse in any 3.5t wagon Im afraid. I think the payloads about 1100 or 1200kg. I know of someone trying to sell hers for that reason.