Those are good guidelines, assuming you can do the 'longer saturday distances' comfortably. (starting at 30 or 40).
If you find yourself sore or dragging at the end of a week, you can just back off and repeat a week or two till you end up
feeling stronger - let your body be the judge.
Also, as you get to the longer rides, ride nutrition becomes an important factor - you need to eat as you go or else you'll hit
the wall. Look around the training forum for some ideas.