Use the sim time to learn the hold entries and other procedures, making drift calculations while airborne etc so that you don't have to think about them. You will be busy enough in the real aircraft without having to remember 60/tas x windspeed = max drift or something.
Depending on the package, sim time is a fraction of the price of the aircraft, so it is never time wasted. I did a non-approved IR and spent some 10 hours bashing the sim before I got in the aircraft, and the result was I only needed three trips in the aircraft including the 170A before getting a first time pass. This is not meant as a boast, but simply to illustrate that I felt able to handle any type of procedure or airborne calculation before I actually got into the aircraft because I was able to use the sim, pause it if necessary and so on until I knew where I was.
Make the most of the sim time, it's not costing you £30 a click!!