What paperwork fits this situation?

[Amin Brodie]

I just started building tiny homes in my hometown in Eastern Texas. I have a customer that wants to order a number (~25) of my tiny homes through his company in connection with a city initiative to provide unconventional housing options in their city, also in Texas. I agreed to send a model unit to his city so that he can have his engineers and architects inspect them as well as have an open for potential residents. He will not be buying the model unit, it will simply stay for four weeks and then be taken back to my yard. He plans to place the unit on some land that his company owns and he has a narrow deadline that he has to meet in order to submit his bid. What type of considerations should I think of and what type of paperwork should I have for this situation? All help is appreciated.