I found that I had to add Tamiya flat red to Hull Red to get my Yamato hull accurate. From all research done.
I did the same thing to a lesser extent with my Bismark. Once you know the shade for your Tirpitz, just add flat red until you are satisfied.
I use MM mostly yet find the Tamiya's will airbrush well and are quite resilient when completely cured. I also have used Testors flat laquer on every hull once the paint has cured, and then washed with thinner and black artist oils in order to reduce contrast and add reality to the paint job.