rather than ask "how much they'd be willing to pay", it might be more compelling to simply say "It will cost $X for early access, limited to X slots, in exchange, {we do such-and-such}."
If they say "OK, great", you've got immediate revenue to bring back to your management, and a strong case to continue doing more of the same.
Customers routinely over-and-under-estimate future value, compared to what they're then willing to pay.
They're often wrong in both directions, they usually won't pay as much as they think they will, _and_ they'll often pay far more than they think you will.
There are many, many reasons for both kinds of errors, many of which can be de-risked in advance and safely ameliorated.
