I have BM Stonington Gray in a low light, SE facing bedroom and it looks very bluish gray to me - which still surprises me when I look at Stonington Gray in spaces with more natural light! Good luck!

Try BM Silver Lake. It's not one of the historical colors, but it may give you the bluish gray you're looking for. My son used it in an east facing bedroom in N. VA and we used it in a north facing LR here in CA. Great in both, but a totally different color in our north facing bedroom. We used BM Stonington Gray in that bedroom, which looks very neutral gray with just a hint of blue undertones.

Because our bedroom was so difficult, we had color chips taped to the walls for several weeks before we narrowed it down to a handful and started painting actual swatches. Things we thought would be great weren't and Stonington was a third choice surprise. You never know until you see it in place.