Trouble getting tee assembly off of a Kohler Revival

Thanks to the fine folks on this site, I am undertaking some simple DIY projects and have hit a snag in my first one.

I am trying to remove and replace a Kohler Revival wide spread bathroom sink faucet and I can not get the tee assembly off of the underside of the spout. There doesn't appear to be much to leverage, given that the assembly is mostly round and the spout is already loose.

Any hints or tricks?

Also, any recommendations for a basin wrench that will help with the handles? The standard issue one I purchased can't seem to turn the nute.

Thanks!

Fred

Plumbers don't waste time on rusted threads, they cut/saw them off. Be careful not to damage the counter top and other things along the way.

A Dremel tool is a useful thing to have in the bag if you are cutting the metal but want to do fine enough work not to damage anything else. Leave the Sawzall elsewhere, for example.