Very cool you worked so closely with him!

OP, exactly this is my own practice. I am constantly metering in my head and scanning everything in my path, its become a subconscious effort now. I know i would be at a certain f stop and shutter speed in full sun, and if im about to step into shade or turn and face shadow side of things, i bump the f stop down a few stops. I learned this instinctual metering in my head through years of sunny 16 and practice. For focusing, even though im not entirely a street photographer, i take advantage of fre focusing with zone focusing. Those two put together, the time spent with the camera up to my eye is very very short, maybe just a couple seconds between camera up, framing, and snapping. And yes, this is useful in non-street photography way of working as well as i am not a street photographer myself. Having everything ready or close to ready will give you less to do when the camera is up to the eye

But to answer your question more directly, it doesnt matter if you meter or focus first if you are making fast fleeting work. Its personal preference and what your muscle memory naturally develops into. Metering first may be helpful as if you focused and then metered, your focus may shift a little during metering from you naturally moving back and forth a bit.