I'd be pretty content with 24mp... the 6000 x 4000 resolution matches that of the top slide scanners without the noise.
A noise free 24mp file is a thing of beauty to work with. I've always contended that 12mp was enough, but give me more, and I'll take it. Ask my in 3-5 years... I may have changed my mind again but for now 24mp will do me just fine.