Yes, that is my understanding also, as far as amount of time. I understood the original question to be regarding optimal SET, as in active and meditation and which order. In terms of both that question and yours, I think the best would be TWO hours of active, followed by ONE hour of Small Universe, and then ending with some variation of ending exercise/harvesting qi.
And then, including Self-Concentration at the end, I see as gravy or icing (or Butterfly Healing Meditation or one of the other variations on Self-Concentration, such as the excellent meditation in the EUPHORIA! course from LSC. That meditation has been offered as a free bonus download for all kinds of things. I don't have the Euphoria course, and know nothing else about it, other than that Master Lin guided meditation, which as Shawn has described it, is somewhere in between the Self-Concentration and the Butterfly Meditation, both in terms of pace and length of time).
I kind of use the Self-Concentration meditation and its variations as either a break during the day or a little "qigong nap". I rarely use them as part of my regular SFQ routine. But to each their own, and it might be good, better or best for some people to do so. Actually, lately, I have been using that free download of the 15 minute meditation Master Lin offered back a few months ago for my little break. I like that one a lot for that! Short, sweet and very healing. I now use it a lot like I sometimes use the 10 MInute Supercharger Paraliminal (still my favorite Paraliminal!).
But, yeah, two hours is best for active exercise, one hour is better, half hour is good (in reverse order!

).
And then for when to do meditation, best is after active exercise.

I thought that "optimal" would be two hour sessions of active, following the "seasons" Spring, Summer, fall, Winter. Qi circulates every half hours correct?
JEFF