Q: “When I do my simulator training on iRacing should I focus more on doing races with other people, or doing private test sessions to practice specific skills?”
A: It depends on what your goals are, and more importantly, what you see needing the most improvement. When coaching drivers I always look at three areas: outright speed, racecraft, and track knowledge. Then I focus my coaching on one area as much as I can, and that gives the best results. With your driving, is outright speed more important than racecraft? If so, do private test sessions to focus on specific skills to improve your speed. If racecraft is more important, do more races. If it’s track knowledge, then practice sessions are your best bet. Look at what your objectives are, and then decide from there. And I think using the Speed, Racecraft or Track method of determining your objectives is a good way to approach it.