Most manuals and tyre manufacturers recommend 36-42. But this is for a middlewight bike, loaded, and with a pillion. So not really relevant to the Tuono.
Have a play around within those pressures, and see what you like, you shouldn't be far out.
Getting really accurate tyre pressures is more or less impossible for most, given that to measure it, you need to have a known ambient air temp, how recently the air was compressed (still holding heat) and the accuracy of the guage you use (no two are ever the same)
Experiment with a few pressures, you'll soon discover what works for you.