I have successfully linearised Museo Portfolio Rag with a reduced density curve from PhotoRag - and I get a Dmax of 1.80!
Since I was not very sure about the best gammma curve, I was testing Dotgain 20 against Gamma 2.2. The result is, that Dotgain 20 looks better/closer to the original image on the screen (on screen it looks the same).
I had the same in StudioPrint but was guessing that it should not matter what curve to take in Print Tool. What is your experience?