The brazing tip I use for doing fork crown brazing to either a steerer or blades is a G-Tec 3-TEN tip. Don't confuse this tip with any other brand including Genetic and their TEN tips. These TEN tips have no relation in size to the Victor TEN tips for propane. This G-tec multi-port tip is WAY bigger than any Paige tip. The center orifice is .062" (about the size of a Victor #3) and the six side orifices surrounding the center hole are around .030" + (meaning a little bigger than 30 thousandths of an inch each). In other words each side hole is as big as a Victor #0 tip. And there are 6 of them. The center flame is nice and sharp while the side flames stabilize the flame to keep it from blowing out with gas pressure blow back. I prefer this tip much more than a rose bud for fork brazing because of the sharp flame point coming out of the center hole that is great for cleaning shorelines. I run this tip with my Devilbiss 5 lpm model 515 oxygen concentrator. Works great. A Devilbiss concentrator puts out more oxygen than other brands.
The G-tec company: <https://www.gas-tec.com/torchtips> also makes their single orifice TEN tips (NOT to be confused with the sizing on their TEN multi-port tips) out of brass instead of copper. These are Victor TEN single orifice clones for propane brazing too. They are the cheapest place I know to buy Victor style TEN tips. They were out of some sizes between 0 and 5.
Tom, I applaud your willingness to experiment with how to make a fork. I must say that the one place I would not try and use brass is brazing the steerer to the crown. It is so much easier to use silver and it doesn't take that much. If you are in a production setting and brazing forks the way budgie does, then cranking up the heat and doing the steerer and crown all in one go with brass makes the most sense. I'll explain in another post why it is easier for amateurs to separate that procedure. For starters it reduces the skill level needed and is more likely to get better results. The skill level Mark has is huge compared to most amateurs.