A 1/5th acre pond is pretty small for large F1 bass. Like you, I also like unconventional, potentially "dangerous" plans. Potential plan of that type below:
One plan would be to put the F1 bass initially in your main pond. Any you catch during a subsequent spring spawn that are OBVIOUSLY females could be moved over to the small pond. A small number of bass with zero population reproduction might work fine in a pond of that size.
P.S. Have you seen any of your stocked BG this fall? If you can estimate the size and numbers, then some of the "fishery balance" experts on the forum might be able to give you some good advice for your next step.
