[txwanderer]

Try plain english. I am sure they have heard it and since they are the seat builders, let them build it. You know what you are looking for and the position you want and cahanges you want. Tell them your goals and let them figure out how to do it, that is what you are paying them for. Be spacific, send pics of you RIDING if possible, instead of sitting on the seat. Tell them every detail of what you need and want. That will help them a lot.
Most of the time just a simple direct conversation will work better than anything else.
Good Luck.