I'm not sure that I follow your logic or arithmetic. You say by walking rather than riding, you can carry an extra 700 pounds. Admitting that I have no experience with llamas, I dont know what they are capable of. I would'nt imagine though that they could carry as much as a horse, which is something that I am very familiar with. Anyone who has ever packed will tell you that the most you should pack on a horse is 200 pounds. And yes, someone will ask, what about a person who weighs over that riding. A person horseback is alot different than a horse packing the same weight. When you pack and pack right, that weight is tied down securely and very snug. If the pack moves, you have not done a good job in your packing. An overloaded or poorly packed horse will come up lame and with bad saddle sores and will leave you on the side of the trail with no way to move your gear. A person riding does all of his moving and maneuvering on a saddle that is tied down snug. If it isnt, again, you will sore your horse. Anyhow, a rider can help the horse carrying his weight by maintaining his balance. A pack cant do this. It is dead weight. If a person is unfamiliar with horsepacking, please take a class and learn to do it properly before you start. Your horse will thank you.
The optimum size for a packhorse is around 14 hands and around 1000-1050 pounds. The reason for this is ease of packing and getting the most use per pounds of horseflesh. It is much easier to pack a smaller horse compared to trying to load and properly lash down a pack on a draft type horse. Also, you will not be able to pack enough weight on a drafthorse to justify their feed needs. Smaller horses are easier to pack, easier on feed and easier to care for than the bigger draft breeds.
I hope this helps.
Tex
