This ngon-dro is a gong-ter revealed specifically for Jetsun Pema Rinpoche
and Her (i.e., Mr. Kazi's) Western students by H.H. Dudjom Rinpoche. So first of all, if you have received it from a bona fide source (which you have), Guru Rinpoche intended it for you. What an incredible thought! Because it is so fresh, it carries incredible blessings and swift accomplishment. As Mr. Kazi used to say (and Susan [haydenlaw] hinted at above, it is not just a ngon-dro. It is the kind of very simple Dzogchen sadhana a highly accomplished yogi might do after having completed so many other, more complex and extensive sadhanas. So don't undervalue this sadhana. Mr. Kazi did it every single day, and He received it after He was realized.
In terms of its being a ngon-dro, you can pretty much finish each of its five sections in 3-4 days each (four 3-hour sessions per day). So just do it.
As Susan has also said, Mr. Kazi gave His students the Longchen Nyingthig ngon-dro after completing this short ngon-dro. However, you could easily make this short ngon-dro your lifetime practice. It's not lacking anything. Whether other Teachers would/will accept this ngon-dro before allowing you to go on to other practices, that's up to Them. But you shouldn't think that this practice is higher than that practice. Really accomplish any one practice and the two purposes (of self and others) are served. Remember that the great Guru, Khyentse Wangpo realized while doing Vajrasattvas within ngon-dro. Also remember that H.H. Chatral Rinpoche has done 14 ngon-dro.
Today is Mr. Kazi's three-year parinirvana anniversary; so I'm off to my cushion. Good luck and best wishes.