“The people are first time owners and buyers buying on their trainers recommendations sight unseen and untried.”
No, you do not sell a horse to people like this. First time owners is bad enough, but NOT even trying or seeing the horse. Heck no! This is a disaster waiting to happen.
And a trial or a buy back. No! The horse will not work out for them. They don’t know anything and will want to return. You are not Nordstrom’s where they take any kind of return.
Just say no thanks. I feel this is not a good situation for my horse. And then run like hell. There is no need in the current market to even entertain this buyer. You would have to be desperate. Are you desperate?
I sell horses all the time. I do sell horse to situations where the buyer does not come see the horse. That is fine for me for a foal and youngster assuming the buyer is experienced. First time buyer, buying for a kid, then the answer is no. Any riding horse – you need to come try the horse to be sure the horse suits and I need to be happy that it is match. I have no problem selling this way and I sleep well at night because I know I did my level best for the horse.
So to the OP, there is nothing to negotiate. You can’t sell the horse to these people. It is not the trial it is the buyer that is the problem. Huge Red Flag IMO.