I agree.. The details are completely between you and the other breeder. Always do research on the other breeder. Its best if you already know the other breeder in person. agree on and make up a written contract and have it notarized. Then make copies for each of you. If money is asked for upfront, make sure details are included in the contract to cover any loses if something goes wrong.. Like the female doesnt become gravid, one of the parent snakes gets sick the eggs are slugs, the babies are defective or not the colors/morphs agreed apon etc..
I myself am using a Spider male which is not mine, for breeding this year. The details have not yet been set in stone because im considering buying him outright. If i do not buy tho, the breeders im taking him from are people i personally know and we will have a written agreement explaining the equal divide of hatchlings depending on sex, and that i will cover any vet costs if their male gets sick or injured while in my possesion.. I probably will have to put up a refundable security deposit before i can bring him home with me. In that case, it will also be included in the contract we make.
These are all things to consider.