+1 on Ryane's reply. Blending is a good thing. As you repitch sour slurries you have no control over the balance of the microbes hence the "wild" aspect of the process. The last thing you want is an overabundance of pedio resulting in a butter bomb. I know someone who keeps a sour house strain with waaaay too much pedio out of balance and he makes a very nice butter-kriek (friendly sarcasm here).
I buy the balanced Wyeast mixes and then pitch dregs if the mixes don't do what I want them to. It's a gamble every time but it eventually works. Just give it time. And most sour projects will "clean up" after several months too.
However don't pitch too many dregs from commercial bottles, and don't pitch old ones. Quick story:
A friend had a sour tasting after bringing a ridiculous amount of sour commercial bottles back from Belgium. No joke - every lambic brewery was represented. 22 bottles, ranging from new creations to "vintage" bottles from 98. I collected most of the dregs from all of these bottles...and pitched them into a batch of lambic. 4 months later I had wonderful batch of nail polish remover. Acetobacter was completely out of control...it actually burned my nose. Unblendable. I was forced to dump the batch.
Primary: Saison w/Dupont strain
Secondary: Belgian Pale, Saison d'Lupulin, Farmhouse IPA
Kegged: Saison d'Lupulin
Sour Secondary: Cabernet Oud Bruin, Sour Cherry Oud Bruin, Sour Ale base, Kriek, Wild Night, Wild Night w/Blueberries, Wild Noel
Sour Cellared: Cabernet Lambic, Wild American, Merlot Lambic, Namaste Golden Ale, Saison Twenty-Three, Spring Equinox Saison, Belgian Pale, Orval Clone, Chardonnay Saison, Sour Cherry Saison, Cabernet Flemish Red, Bordeaux Lambic