So, this'll depend a lot on how long you want to age it. Are you just looking for funk or do you want it to drift into sour territory? Your recipe and technique seem sound.
I've had incredibly good luck with White Labs American Farmhouse strain. It makes sellable beer in about 30 days and then the character evolves over the coming months. If you're going to bottle it and want your customers to store it, this is a pretty good choice, IMO. I've also foregone the barrel and just aged them in kegs.
I've found that I like the Brett Lambicus strain best. However, it's one of the harder strains to eradicate from the brewery, once it gets entrenched. I treat it with the same caution I'd give acid... that was on fire. Everything except barrels gets hot caustic followed by an acid rinse and paracetic sanitizer. Barrels get a hot water wash with both potassium and sodium metabisulfate, if I need to neutralize them.