as a machinist and welder by trade, the answer is about always "bolt on" when given the choice. if you can make something bolt together instead of weld together without much more effort, the serviceability is well worth it.I first started out looking at the weld on due to the cost savings since a lot of people have success with weld on. After researching the weld on and talking to a company that is one of the common top choices they said if your going to run it like an Ultra4 don't run a weld on, get a bolt on.
I would have no problem welding it with with the correct methods. But I still never was comfortable with the idea. I decided bolt on was the way to go so I could sleep at night and not dream of having the high steer break off and cause me to drive off a cliff and burn to death in a pile of twisted metal.
Bolt on methods varied so much as well as options for sending the knuckles out. By the time I was done researching. I saw the high steer in my head and figured it was easy enough to weld up a high steer bracket and drill and tap the knuckle and mount it. This allowed to put the tie rod location exactly where I wanted it. The bolt on design also grabbed the knuckle over more area than most key or step using smaller studs in a concentrated area. In the end I'm confident it is the strongest solution using the stock knuckle. Going to an aftermarket knuckle designed for high steer would be a better solution but I can not justify the cost and need.
Pictures of it can be found on IG @Dustdynamics