I've been running a 338/375 Ruger in an 18" barreled SP for about 5 years and the case capacity is nearly identical to the 330 Dakota.
My favorite powders with almost every bullet weight are H4350 and H100-V. A friend who cut a rifle barrel with my reamer had very good luck with 7828 out of his longer barrel. I've had the best luck with bullets in the 225-250 range. The 300s are just too heavy for the relatively small case capacity. The 250 SMK is a phenomenal shooter in my barrel for target work and the 225 TTXS shoots great for hunting.
Andrew