I havn't seen any credible research about cee pointing to ANY dosage times, merely peoples personal experience and results and lable directions. I would be interested to see this research of which you speak.
That being said, 1-2 has always worked best for me, has been the concensus with those I spoke with, and is basicly what my lable says as well
*Reads from bottle of VPX CEX* "Always utilize the cex strategy two hours prior to resistance training"
In the long run I highly doubt if there is even a difference between 1hour 2 hours or 30min. Take it when YOU feel it best.