I usually unlock one "layer" at a time. Now, for each layer I have the nodes I unlock first, but then I unlock the other ones in that tier usually after that.
Wow, I had only seen the picture in the OP before now! Those pics in the last few pages are amazing! I wanna go visit Dres now looking for a white spot.
Or you could use a bunch of RT-10s on top of each other with decouplers. Each time a booster runs out, stage it away and fire up the next one in the line. (CoT would move way up though and that might cause problems....)