If we have a summer like 1976 you will be ahead of the game. They tolerate drought so not convinced they will like our cool damp summers. I would suggest also trying the greenhouse border as well, inside may be too humid.
Seems guar is somehow used in the oil fraking process so the world price is rising. People who use it instead of gluten might be pleased to be able to grow their own,
Good luck with your experiment. Eagerly awaiting the results. Even if you get a poor crop a few beans might do better the second year.