Basically have a look at what key attributes you need for each position, those are the ones you need to concentrate more on when designing a schedule, for example a CB doesn't need too much training on shooting and set pieces, so these can be set lower and you can then increase training on defending and tactics...
Personally I like to keep all levels within "medium" and if possible "high" to give that all round training programme, however keep the overall training below intensive!
Hope that helps? Any more questions just ask...