Wow, thas a LOT of caffine per serving, unless that is standardized down to about ~200mg active... If I remember correctly the old xenadrine dose was:
20mg ephedra alkaloids
15mg salicin (asprin)
They reccomended that dose 2x a day, no later than ~6 hours before bed unless you wanted to stay up all night. I use a home-made ECA stack that has
25mg ephedrine HCL
and I love it, I use that much asprin because it's the smallest one I can find around here (80mg and I split it). Sometimes I split a dose up as well. I'm loving this combination right now.