That is a nice starting point for plenty of beers, just not so much for a stout. Adding calcium and other flavor ions will be no problem, but you will need some alkalinity to maintain the mash pH. I see from Yooper's recipe that there is a decent amount of crystal and roast malts, so its likely that the mash pH would be low.
Lime addition is the most sure option for adding alkalinity. You could also use baking soda, but I'm doubting you could get enough alkalinity in the mash water without adding too much sodium. Chalk may be too much trouble to prepare so that it is fully dissolved and it doesn't add alkalinity reliably if you just add the powder to the mash.