Double check my numbers here

So I'm about to send off my ward labs sample to get a definitive answer on my exact water profile but in the meantime I'm brewing a black IPA and want to adjust my mash ph and tweak my chloride/sulfate ratio. The water here is pretty good from what I'm seeing except it's high in bicarbonates...from 140-200. I have gotten a couple different profiles from brewers around me(we all get our water from the same source) and they are all very very close so I feel confident rolling with their numbers until I get my results.

That said my current water from the tap is:

Ca - 30ppm
Mg - 17ppm
Na - 5ppm
SO4 - 12ppm
Cl - 7ppm
HCO3 - 160-180

Throwing this in EZ water for an 11 gallon batch(33lb of grain) to get a mash ph of 5.4(room temp)
I need to add 10ml of Lactic Acid (88%), and I was going to bump up the chloride and sulfate a bit with gypsum(8g) and calc chloride(6g)

My resulting profile would look like this:

Ca - 107
Mg - 17
Na - 5
SO4 - 112
Cl - 72

Is this looking like an reasonable water profile for what I'm shooting for?
Any tips, advice, would be hugely helpful.

I'm still wrapping my head around water chemistry but from what I'm understanding mash ph is by far the most critical and salts are just like spices in a soup, just meant to tweak flavor. I finally bought a nice ph meter so I'm looking forward to testing the real world numbers on this and perfecting my brews. At this point I know water chemistry is what's holding me back from my brews being the best they can be.

Thanks!

Those levels of bicarbonate imply alkalinity of 2.62 - 2.96 mEq/L and you will need about 90% of that to get the water itself to mash pH say 2.3 - 2.7 mEq/L. 88% lactic is about 12N so you will need approximately 2.5/12 = 0.2 mL of lactic for each liter of water treated. Assuming you treat the whole volume of about 13 gal (given you are making 11 gal beer and allowing 2 gal for losses) that would be 13*3.785*0.2 = 10.45 mL. You will then need additional acid to overcome the alkalinity of the grains depending on whether 'black' comes from Sinamar or some roast malts. If from roast malt you might need less than 10.45 mL.

Given that you have a pH meter and a rough idea the smart thing to do is make a small test mash and check its pH.

Thanks for the detailed info aj. Im currently getting used to the spreadsheet and ranges and whatnot but its always nice to know how the numbers are coming about.

So it would seem that my amount of lactic was about right on the money then considering I do have a small amount of roasted grain.

What about my other additions? Does that seem like reasonable amounts and whatnot.