John, you might be ready to 'clip your wings' and quit your day job.
You are on your, what, second frame build
ever?!? 
Looking gooooood!
The Scrapper 2015
Mid-Western Flyer X-16 2016
Black Cat 13 BO13, 2017
A Zombie Reborn 2022
Well... 5th in Build Offs, two before I discovered RRB, and some less that stellar ones on the side.
Also, my day job is paying a ridiculous amount right now, so, I'll keep bikes in the Hobby category for the time being.
But, I'm getting better. Lots of University of Youtube. (Welding Tips and Tricks, Pithy Bikes, Cobra Framebuilding, So many RRB members..., others not coming to mind right now...)
Sharing because that is how I've learned. Tools can be hacked, but sometimes the right tool makes the job so much easier and better (i.e. frame jigs & headset presses for alignment,) and I've built the tools up one by one over the years.
Welding with Pulse
can help with the welding, but won't make you a better welder. I'm still learning that. I should take a proper welding class, but, time... I learned the basics when I worked manufacturing years ago, most of the rest via internet and trial/error.
Sharing this kind of info that is useful to people years down the track is part of what makes you builders such an inspiration.
Trying to give back to the community what I've learned from those who came before.
For mitering specifically, the best setup is a quality mill for steady cuts and the proper tooling/jigs for the angles. (i.e. Cobra Framebuilding) A less expensive, (and smaller) mini-mill can do the job (i.e. Pithy Bikes) but most require some mods to make reliable, and also a quality stable work bench. (mine is cheap and wobbly.) The HF notcher worked for me for some time, but is an admittedly inexpensive tool with a brass busing/bearing instead of needle bearings like some more expensive versions, and has become wobbly over the years. My HF drill press spindle is also a little wobbly.
My first adventures were with thicker walled tubing and were more forgiving. Thin-walls allow lighter weight (my first build was 1.5"x0.083 wall and weighed 80lbs bare frame! Thank goodness it was electric!) and thin walls are easier to work by hand, but harder to bend, and harder to weld.
And... I still don't have a tubing roller or proper bender. All my bends have been with EMT conduit benders, which don't work on thinner than 0.049", and not even well then. I'm too lazy to do the fill-with-sand-and-cap method.
Funny I can run beautiful test beads, and the lap joint of the seat tube buffer went well enough, but once putting the tubes together the end of incoming tube really wants to just melt away. ¯\_(ツ)_/¯ 
