Looks great so far my brother. Time for me to chip in on this massive thread...
Scribe the forks with a sharp point around the top of the triple tree bracket. Cut below that line with any cutter you want or are comfortable with. The top bracket will cover any line or imperfection and as long as you don't use the big thick cutter from Harbor Freight. The roller on that cutter is wider than the bracket and might leave a mark. But the rest of it is easy don't overthink it don't worry, just cut it below your scribed line as close to it as you can. That's taking for granted that you'd be using caps with jamnuts inside the tube. But either way the top of the bracket should hide the cutline within reason...
Carl.
Thanks for the helpful tips. The cutting should go fine. I have these machined caps with o-rings that go on top and dress it up.