Mine's got about a half inch nozzle, so probably similar to the T-4 tip. It seems like it consumes more gas than half a pound per hour, but I have no idea what pressure the regulator (and yes, the shutoff of the cheap turbotorch I have does have a regulator, not just a needle valve) is putting out.
I got the canti posts pretty hot for a longer time and kept the heat on the frame to a minimum, just drawing it over until the bronze flowed well and I achieved proper penetration. I used this technique because I knew the posts had the most thermal mass, so they'd require more time to get up to temp, and it's less critical if you overheat whatever mild steel they are made of. I'd think you wouldn't want a tip that's larger than the posts, if you wanted to use this technique.
Ron Cooper has
spoken about his time at Gillot's and mentions that the old guard learned to braze on a coal-fired forge. Oven brazing was also used by Rudge in Nottingham (see video, about 5:00). These were thicker walled tubings no doubt.
I am trying to do things similar to what I've seen framebuilders do with oxy-fuel. With a little adaptations in technique, it seems acceptable. I see a similar heat-affected area to what I've seen from professionals.