... just don't think it work well with the single bungee.
Yes, but you think that even confronted with contrary evidence (see picture linked above).
Around me everyone uses single bungee (after some time knowing me and the instructors I regularly dive with).
All (those who try) are able to dive heavy steels with it, on Razors, Stealths, Diamonds, Hollis, Toddys, build-your-owns, any existing system more or less.
It is not the optimal system for heavy tanks, but has other advantages and can carry any tank type or size at least 'good enough'.
... I am not a fanboy like Razorista....
I am not a fanboy, ask HP, I am one of the people most critical and discuss everything form several points of view with him, when I get the chance.
The Razor is a tool for me and I would mothball it without regret or hesitation if something better comes along.
I just believe that is highly unlikely to happen soon.
I know how sidemount works quite well in theorie and practical application and the Razor is a 'perfect' system to choose to have a very easy transition.
That is not something I make up, I can prove that by my own example and by many other examples as well.