I have found that using a big camera on a tripod makes me transparent when doing street photography.
I set up by prefocussing and framing on an interesting spot, shop window, ticket booth, fountain, and the like, where interesting looking people may do quirky things. I watch the unfolding scene attentively but casually and I never look at anyone through the camera. Sometimes the reflection in the lens filter tells me my "target" is in the right spot. Because I fuss with the camera controls, make meter readings, occasionally press the cable release, wind the film while standing in front of the camera, no one knows (or seems to care) when I have made an exposure or who has been photographed; not even the small, easily bored, transient crowd that pauses to watch what I do!
My most "conspicuous" camera is the Mamiya RB 67, a TLR is even less visible, and the 8x10 view camera may as well not be there at all. City crowds mind their own business. If they do not perceive themselves to be in a predator/prey relationship to the guy with the camera they move on without flinching. Drunks passed out in gutters get the same treatment; they may be seen but are not looked at.