1000w is plenty and more for an 810e.
Agreed. Running 700w RMS into my 810E was more than I've ever needed. My SVT-II was still hanging in there through that hour but it was at it's absolute useful volume limit. Anything farther was useless but cool sounding deep overdrive.
If it's for ego, fun, and tone, get the SVT-CL. Trust me. I picked up another ~300w tube amp today after having sold two SVT's already. Guess I can't go without them!