The link is the latest info. I would chronograph any load you try as all of Savage's date seems high on the velocity. don't know of any sabot manufacturers offering load data. Second link has lots of info on the Savage including loads. As for 777 versus smokeless couple things. First check if smokeless is legal. Second smokeless is way more reliable and temperature stable. Might not give you that much more performance but it will more consistent. If legal I would go smokeless.

https://s3.amazonaws.com/savagefiles/manuals/manual_muzzleloader_10mlii.pdf

http://randywakeman.com/savage3.htm