I find that most of my coordination comes from my hands getting used to doing things and my eyes are just so I can see if I did it right. I often think of it more as a combo. Making it less about reaction, you may be able to plan ahead and make adjustments to your timing. Like if you see yourself land on the ground and it takes you half a second to react by sparking into the slope, then schedule your visual cue half a second earlier.
I guess the main problem is that that tank just makes it a much longer combo to plan. Even if you have good reaction time, it still takes several tries. :^\
I assume she means the one right after the chozo test that you have to charge a shine in the pool that has the supermissile in it, spark up a couple platforms to the top of the room, then break the blocks up there and drop to the mid-section of the long shaft and spark left to recharge, then drop a bit further and spark through from Chozodia to the mother ship.