NYC Water Chemistry for an Imperial Stout

I take it that NYC tap water is very soft with very low residual alkalinity. So if I'm doing a mini-mash for an imperial stout, should I be worried about pH dropping too low? I've been thinking about trying a pH stabilizer, or just adding some baking soda (budget option). Or maybe I just shouldn't stress about it?

5 gal recipe with a 5lb mini-mash consisting of:
3.00lbs Base Malt
0.75lbs Chocolate Malt
0.75lbs Roasted Barley
0.50lbs Flaked Barley

But a lot of the OG will be from extracts to get to about 1.100.

I wouldn't worry about it.

I add some gypsum and some salt to my "lighter" beers, basically those that have less specialty grains. Anything with a lot of specialty grains, I leave the mineral additions out.

i can't say i've done much research into it but i've brewed an imperial stout and it turned out quite well. it was my most popular beer at thanksgiving last night haha