Sorry to revive the thread a bit, but figured I'd input my limited experience with this strain.
I've got a 10 gallon split batch that was kettle soured with the swanson veggie capsules sitting in fermenters now.
The recipe/process I followed is:
(for 10 gallons)
Prepare 2L starter with 180g DME, 40g Table sugar, 30g Calcium Carbonate, and 2g DAP. Add 3 capsules worth of L. Plantarum and purge with co2, rubberbanding cling wrap onto the top of the flask. Let sit for 48 hours.
On the day of the mash, the recipe was:
9lb Avangard Pils
6lb Briess Flaked Wheat
1lb Acidulated
Mash at 153*F. Vorlauf, fly sparge and collect 12.5 Gallons of 1.033 wort in the kettle.
I let the wort in the kettle cool to 90*F overnight, then pitched the starter (minus the caked calcium carbonate on the bottom) into it. I didn't boil, then chill...mostly because I had to work the next day and just didn't feel like it. Purged the headspace with co2, and wrapped the top with cling wrap and rubberbands as well. I periodically purged the headspace with co2 over the course of 48 hours to limit acetic acid production (2-3 times per day). No hops were added to the mash or pre-lacto, as I had read this strain can be finicky with IBU levels above ~5.
I made two 1.5L yeast starters from rinsed yeast from previous batches. To do this, I simply drained the souring wort off into erlenmeyers, boiled it, then chilled and made starters as normal. I wanted to acclimate the yeast to an already partially acidic environment during their growth so they wouldn't be shocked with a low pH when introduced to the full wort volume. It worked well, actually, and making the starters was quick and easy. One batch got WLP001, the other WLP644 (Sacch "Brett" Trois).
On brew day I boiled for 60 minutes (mostly to hit the 1.037 gravity I was shooting for, and reduce the volume in the kettle) with no hop additions. Chilled as normal, then split into two carboys and pitched the yeast starters. I will note that the hot break was INSANE. The foam created was so thick that it was almost the texture of whipped egg whites on lemon meringue pie. Very interesting. The boil definitely "smelled sour" ...kind of like apple cider vinegar but not quite. I'm not great at picking these things out!
Fermentation took off just as quickly as any other clean beer I've made. After about two weeks I decided to start taking gravity and pH readings.
WLP001 - 1.010 FG, 3.00 pH
WLP644 - 1.008 FG, 2.96 pH
With as ridiculously low of a pH these beers have, you'd expect them to be very, very sour. They're certainly bracing, but not to the point that you don't want to come back for more. The lacto provides a fruity/citrusy sourness, but the FG is high enough on these beers that it's not aggressive to the point of being unpleasant. Unfortunately I was waiting on a replacement pH meter probe so I was unable to measure the pH drop in the kettle.
Because I can't leave well enough alone, I currently have the WLP644 version sitting on 3.5lbs of pluot puree, and the WLP001 version with 2oz Mosaic in the dry hop.
My club will be pouring at NHC this year on club night, and I plan on bringing the Pluot version along, so long as something doesn't go catastrophically wrong in the mean time!