Critique My Water for an Oatmeal Stout

I'm trying to build a water profile from distilled water for an oatmeal stout. Here's the recipe:

5 lb. 10 oz. British pale 3L
0 lb. 7 oz. American victory 25L
0 lb. 8 oz. American crystal 40L
0 lb. 8 oz. American chocolate 350L
0 lb. 4 oz. Roasted barley 300L
0 lb. 11 oz. Flaked oats 1L

4 gallons
Color: 75 HCU (~29 SRM)
Bitterness: 27 IBU
OG: 1.055
FG: 1.015
Alcohol: 5.2% v/v

I plan on adjusting the mash water, sparging with distilled water, and then adding the remaining salts to the boil. For the mash, I'm going with a little bit higher alkalinity than for the final beer just to make sure the mash pH is right. For the mash:

Calcium: 79ppm
Magnesium: 5ppm
Sodium: 85ppm
Chloride: 19ppm
Sulfate: 21ppm
Alkalinity as CaCO3: 269ppm
Residual Alkalinity as CaCO3: 209ppm
Estimated SRM: 22-27

For the total water profile:
Calcium: 119ppm
Magnesium: 4ppm
Sodium: 61ppm
Chloride: 17ppm
Sulfate: 18ppm
Alkalinity as CaCO3: 268ppm
Residual Alkalinity as CaCO3: 180ppm
Estimated SRM: 20-25

Obviously the estimated SRM does not match the recipe, but according to this post (and the Dublin water profile) it is probably still good:
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My calcium, magnesium, and RA match the profile of Dublin. I decided to go with a 1:1 chloride to sulfate ratio to make a smoother beer. Here are my concerns. Let me know if I need to fix them or if there's something else wrong that I'm not seeing.

1. The sodium is too high. According to Palmer, high concentrations of sodium and sulfate make a harsh bitterness. You should make one or the other as low as possible, preferably the sodium. Since my sulfate is pretty low, I think I'm OK though.

2. The estimated SRM isn't correct for the recipe. I think this is OK though.

no expert here, but don't you want the sulfate to be higher? I know you are trying to keep the SO4:Cl ratio to 1:1 for a balanced beer, but Palmer suggests "50-150ppm for normally bitter beers" and I remember reading something somewhere recently (likely on this forum) that it's not just the ratio, but also the concentration that matters. Even at 1:1 if the ions are too low, you're beer will be out of balance.

EDIT: Found the post I was thinking of - https://www.homebrewtalk.com/f128/water-chemistry-noob-131191/index5.html#post1523426

That's a good point. The tough part is getting the alkalinity without too much sodium and calcium. If I upped the sulfate, I would be afraid of getting a harsh bitterness. Maybe I can back off on the calcium chloride a bit and get a chloride to sulfate ratio around 0.5. That would accentuate the bitterness more, but probably not make up for the <50ppm sulfate though.

If you just wanted to up the sulfate, you could ad some MgSO4 (Epsom Salts). Your Mg could be raised a bit without too much harm, IMO.

Just don't go crazy, it looks like 1.1g will get you around 11ppm Mg and 47ppm SO4.

I am far from a water expert, this is just another option to raise your SO4 a bit while preventing the Mg ratio from throwing off your SRM range by too much.


edit: Nevermind, I see you are trying to clone Dublin water

For those of you looking back at this post, this beer worked really well with the water profile that I went with. I think it's my best batch out of 8. I don't know if it could have been better with a different water profile, but I'm not going to find out. Here's what I ended up with:

100% distilled water

Mash Water Profile:
2.68 gallons, 1 tsp. Chalk, 1/8 tsp. Calcium Chloride, 1/8 tsp. Epsom Salt, and 3/4 tsp. Baking Soda
Calcium - 83ppm
Magnesium - 5ppm
Sodium - 89ppm
Chloride - 20ppm
Sulfate - 22ppm
RA: 219
SRM: 23-28

Sparge with distilled water.

Salts added to the boil:
2 tsp. Chalk, 1/8 tsp. Calcium Chloride, 1/4 tsp. Epsom Salt, and 5/8 tsp. Baking Soda

Total Water Profile (6.15 gallons):
Calcium - 103ppm
Magnesium - 7ppm
Sodium - 71ppm
Chloride - 18ppm
Sulfate - 28ppm
RA: 191
SRM: 21-26