First sour with Roeselare. Mash pH?

[qmax]

So from what I read, I need to adjust a sour beer mash pH like a normal beer.
Long story short, I ended up adding 28 ml of 40% lactic acid for mash and sparge acidification, that gets me 610 ppm lactate anion in the fermentor.
Now I'm wondering if there will be enough lactic acid produced as it is from the bugs, should have I rather gone for phosphoric to treat my water?
Also what mash pH do you guys suggest for a beer like this?

My alkalinity is 190 ppm as HCO3-, 55 Ca, 14 Mg.
This is my recipe, a variation on Flanders red (these were the only malts I had)

Batch Size: 5.3 gallons (fermentor volume)
Boil Size: 6.9 gallons
OG 1.061
10 IBU
4.4 lb German - Vienna 37 4 38.4%
5.05 lb German - Pilsner 38 1.6 44.1%
1.1 lb German - Munich Light 37 6 9.6%
0.45 lb Belgian - Special B 34 115 3.9%
0.45 lb American - Wheat 38 1.8 3.9%
11.45 lb Total

 

[Oldsock]

You certainly can adjust the mash pH of a sour beer, but it is much less important than a clean beer. Why you ask? Because mash/sparge pH usually sets up things like the boil pH (affecting protein coagulation and hop utilization), reduces tannin extraction, and helps achieve the ideal finished beer pH, things not so important in a sour beer. I can't think of any reason to aim for anything but the middle of the standard range if you are.

The amount of acid it takes to drop the wort from 5.5 to 5.4 (ignoring buffering) is about 1% of what it takes to drop the pH from 3.5 to 3.4. I doubt you'll end up with too much lactic acid (or lactate) as a result of pH adjustments.