The company chosen to oversee one of the biggest developments in the state is asking the suburb of Arden Hills to move its City Hall onto the site and to approve residential buildings as high as 12 stories.

Developer Bob Lux of Alatus LLC on Monday outlined the company’s vision for a town center on hundreds of acres at the site of the old Twin Cities Army Ammunition Plant.

Anticipating criticism, Lux told City Council members, “please don’t throw things at me.”

It has long been clear that crunch time for the megaproject would arrive when a private developer with its own money on the table laid out the type of density and intensity it would need to make Rice Creek Commons profitable.

The idea of building a new City Hall and perhaps also a library and museum drew instant pushback.

“Not sure about moving City Hall, sorry,” said Council Member Brenda Holden. “We’re in the middle of our community right here. That doesn’t hold my interest.”

Others were willing at least to consider it, but the idea of residential towers met a lot of resistance.

Lux and his colleagues outlined a project whose town center would resemble Santana Row, the celebrated Parisian-style development in San Jose, Calif., with waterfront amenities recalling the band shell area on Lake Harriet in Minneapolis.

Another model for a town center featuring movie theaters and restaurants would be St. Louis Park’s West End.

“People from North Oaks and White Bear Lake would be coming here for entertainment and meals,” Lux said. “The people who designed West End are working for us and learned some lessons from it.”

The informal workshop, which also involved commissioners from Ramsey County, a key partner in the project, is expected to be the first of a sequence stretching into autumn.

The key to making the new project a walkable, pleasant environment, the developer stressed — rather than “seas of parking lots” — would be a mass grading of the entire property. That would allow for large stretches of underground parking below commercial and multifamily sites while creating fill to be used elsewhere.

“You would have no competition almost anywhere in the metro area,” he said, adding that the site is within easy driving distance of both big downtowns.

Negotiations, in effect, over the height of buildings began almost at once: It has long been clear that where Ramsey County is comfortable with an urban village, Arden Hills prefers something more suburban.

Asked what he can make work, Lux said that financially speaking, “eight stories would be the minimum” for some town-center areas. “I know it works with 12; if capped, 10 to 12 I know could work, I’d probably say 10. Tour some projects with me and I think you’ll be more comfortable with the height.”

He described the build out as a 10-year process. Alatus won the right to become master developer after a competition against some of the region’s and the nation’s biggest firms, promising a visionary, even “spectacular,” addition to the suburban landscape.

Arden Hills Mayor David Grant murmured: “Eight to 12 stories, we’d need a lot of conversation on that — as well as perhaps the apartments” the developers also propose — promised as “high-end, not low-income.”