I used 10% vinegar for the first couple of months at the direction of my surgeon, adding some lactobacillus to the solution as that just seemed smart.
The more recent studies of MTF microflora have found that we can establish the lactobacilli that is healthy and I think that's what I've got, however I've also checked pH and that remains stubbornly neutral or slightly basic, pH = 7.5-8, rather than the preferred range around 4 or lower. I will eventually talk to my surgeon and gyn about this but for now I'm not worried about it.
One response above says that lactobacilli are something natal females create, that's incorrect, like the bacteria in our guts we get these from outside and living healthy includes having correct microflora.