So a standard 50/50 split is the norm. (unless stated other wise from the start)
The rules are, the male goes to the female, if the owner of the male does not like the idea then don't waste your time with them.
One mating does not always work, it is better to mate the spiders at least 3 times to seal the deal.
Also the driving around with the female is unnecessary strain on the female and might cause the spider not to preform, also the time frame in mating, it can take seconds to days before you get an insertion.
Also the male should be introduced to females enclosure, sometimes does not work like that.
If your female double clutches after 1st egg sack it is still part of the breeding loan.
Breeding loan stands until female has molted out or dies.
If male gets eaten with no insertion then breeding loan is null and void.
If male makes and insertion and gets eaten, breeding loan agreement stands,
If you want to get another male to mate with the same female, then you split the egg sack 3 ways. 50 for first deal and then 25/25 for second deal or depending on what the other males owner agrees to or you can talk to all 3 owners and make a new agreement with an equal split 3 ways.
One needs to ask if the party involved wants to be there on the day you pull the egg sack..
Also Photo's is a must. Documentation from start to finish.
If the male was left with the female for days on end and then gets eaten, you treat the female as mated and the breeding loan stands until egg sack or spider molts out.
What people don't think or take into consideration, is the deli cups and the substrate.
So this is something you should also clear up with the other person, to either divide the cost of the housing (deli cups and substrate) or then you keep a couple of slings to cover that cost.
One thing you need to do and get ready for is the judgment.
Some people tend to think you are laying when you tell them that nothing has happened or the female molted out or the egg sack was a dud or the male got eaten they tend to be a bit suspect.
Some idiots have caused people to not do breeding loans or not to just trust a person.
5 years ago there was more trust in the hobby.
Also be honest from day one, if you have more than one breeding loan of the same species and more than one male inform the persons or person what you have on your breeding schedule.
As an example, I have 2 breeding loans with 2 different people with the same species, 2 different males and 2 different females, 2 different breeding loans.
Also keep record of your conversation and agreements one has agreed to.
Unless you have time and money and have drawn up a contract then you can take the person to court and fight it out to claim what ever came from the breeding loan.
Other wise you cut your loses and run and don't bother doing a breeding loan with that person again, also one needs to prove without a shadow of doubt that the person screwed you over..
Sending an receiving of males, The owner should cover cost getting the spider to you and you must cover the cost of getting the spider back to owner or to the next person on the list.
If the male as one stop use him as fast as possible and send back to owner
If the spider dies while in your care take photo's and inform the owner that the male has died, write something on a piece of paper to proof that the spider is indeed dead and not just a scam from your side.
If the owner brings the male to you and collects the male from you then you can give him 60/50 split for he's effort or you can make a simple deal that you will cover the housing and keep it at 50/50.
The good old art of Bartering!!
Hope that helps.