"I'd hold it at Melbourne Arena where we'd get over 10,000 or even Princes Park where they got 30,000 for Jeff Fenech versus Azumah Nelson," he said.
"He might be 53 years old but he's still a huge name and any of those blokes Hall, Gallen or Sonny Bill would jump at the chance to get into the ring with him.
"It would be enormous."
Amatruda claims he has already begun the process of trying to get Tyson to Australia.
"The first thing I did was contact (celebrity agent) Max Markson and ask him to offer Tyson $1 million," he said. "Max brought him to Australia in 2012. He gets on well with him and his wife but the main thing is that he got him a visa to get into the country back then and that's the key."
Tyson got a visa to visit in Australia in 2012, a week after he was denied one by the New Zealand government, due to being convicted of rape in the US in 1992.
However, this fanciful fight idea will likely have to be put on the shelf until next year due to the coronavirus pandemic, Amatruda admits.
"We'd have to wait until the coronavirus shutdowns are over of course so the fight probably wouldn't be until early next year - as long as we can get the visa."
As for Williams, the former All Blacks midfielder is now with the Toronto Wolfpack in the Super League, and was reported to be in talks to return to the ring next year against Hall, but that too will likely have to wait.
Williams has a 7-0 professional record, but has not fought in a pro bout since 2015, or a charity bout since 2018.
Assuming he's not an undercover codehead or surprise oval ball fanatic, the prospect of fighting Williams would probably mean nothing more to Tyson than the money that would accompany it, but give Amatruda one thing - he's right that it would certainly create a lot of interest.
As for the likelihood of this proposed fight ever taking place? Well, it's an extreme long shot, but considering it would be solely a money-making venture, there's the slightest kernel of potential, as opposed to if it was being proposed as a serious showdown.
And, when it comes to Sonny Bill Williams rumours, we've definitely seen worse.