Tory,
I have just started playing with my Cooper, but can give you some notes.
Using what I can find on the web concerning load data, I started with H4198. From what I could gather, a middle of the road load would be around 19grs., using a 35 Berger.
I started at 18grs. and worked up. Right off the bat, those loads were showing extreme pressure signs in my rifle. They shot well, but I ended up pulling about half the loads.
I "found" the Cooper load data chart, and it showed that Copper uses 20grs. of H335. I loaded some working up to 20grs. and the pressure signs were gone, and the accuracy was good. My OAL was 1.880" with the Berger.
I just got off the phone with Cooper, and they report their 20VT load is actually 18grs. of H335 with the 32 v-max at an OAL of 1.854"
Hope this helps...