Halo is awesome. I use lower doses than you guys though.
20mg ED for 2 weeks pre-meet is what I did last time and it worked well
Tren, test, drol, and toss halo in towards the end and you are set.
I added it about 4 weeks out just on max effort days, then 2 weeks out went to ED
I also found oral tren to be just as good of a pre-workout boost at 250-500mcg as halo is at 20.
Also, adding a little suspension pre-training/meet in addition to the pre-workout orals seems to bring it to a whole new level for me. Much better of an effect than either alone in higher doses IMO