That sodium level is fine. It could be higher without detriment in this beer, but I wouldn't necessarily go higher.
The sulfate level is fine. Going higher is also acceptable, if you want the beer finish to dry out better. That can be a good thing in a big beer like this. In fact, Burton on Trent was once known for its big beers like the original Imperial Stouts and Burton Ales. High sulfate does not make beers bitter. It makes them finish drier.
I do have concern with the chloride level since high chloride content with high sulfate content is the recipe for minerally beer flavor. If that is your goal, then the chloride content is fine. Lower chloride content would be my preference, but its not a requirement.
Do be sure to include enough bicarbonate in the mashing water to keep the mash pH above 5.4. Many brewers find that a mash pH in the 5.5 to 5.6 range helps smooth out the roast flavors.