It's the Sitnyakovo 4-man chairlift which you use to get to the blue and green you are talking about. It's sort of across and behind the Rila drag lift and Rila 4-man chair, and at the base of the Rila black run.
Using the Sitnyakovo lift you can still get to the Martinovi Baracki blue (and red) runs on the Rila side.
We booked with balkan and it was only £10 dearer (£160)to have a full 6 day ski pack (Skis, boots, unlimited lift pass and 4hrx6day tuition) than it was to have a learn to ski pack. (£150)
Though I wouldn't bother with the tuition unless you're a snowplougher!