Welcome to the forum and good luck with your search. Something to consider…
part of the challenge is going to be that the top deck option is brand new for 2022. I don’t know of anyone with one yet, nor do I believe anyone has gotten one and reported on it in the forum. I don’t even know if any have been delivered yet to new owners since it’s new for 2022.
Thus, I am skeptical if you can get very reliable information in advance because what you do get might be educated, and uneducated, estimates.
That’s in addition to Michiman’s very key point, different trailers will impact height - not all are the same.
All of that said, I am excited Bennington is now offering this sort of option. We were considering a top deck pontoon with slide when we instead ordered our 2017 Bennington. Maybe you and your husband can get one and become our forum source about the new model option…?