I play with real shooting percentages off and I use
zone: 45
short range shots: 45
midrange shots: 48
3pt shots: 47
layup success: 45
and get very realistic results. I can check my association stats for you later to tell you my averages.
These slider settings are used under the assumption that you know your player's shot releases very well. I play with shot release timing feedback 'off', but in practice mode I can see that I hit most of my shots in the green.