I started with the 0.7 grade, and thought it was a really nice tea. There was good body and a strong hui gan with a good buttery aroma that I associate with the high mountain oolong. This tea seemed to steep forever. I'd get 7 or 8 steeps out of it (point of reference ... I use a ton of leaf in my gaiwan -10g/150mL)
Next, I tried the 0.8 grade. It wasn't quite as strong as the 0.7, but it seemed more balanced. The buttery note wasn't as overwhelming. This provided a more delicate and sophisticated profile that was a bit more worthy of contemplative sessions. I've only had 2 sessions, though so far. So I'm not as familiar as the first one.
Now, I'm on to the lower grade 0.4 and finding the buttery note dominates the tea. It's hard to parse out the other notes, because of it.
There is also the way the teas make me feel, but this is harder to nail down. I've only gotten familiar with the first one I opened (dozens of sessions). It really depends on so many factors, that I hesitate to ascribe a certain feeling to a tea. They all make me happy, soooo that's good

Is this typical of assessing different grades? I'm not great at picking out individual tasting notes. Mostly I can only tell the broader strokes a tea hits.