I have learned to never assume a person knows how to do something until I see them do it. Nor do I assume they do not have skills training or experience either.
I can only hope that if a person does not that they will seek out someone who has done a similar act before no matter the simplicity or complexity of the project.
In his first post I noted that he was just unsure about how to make sure it was square. I jumped on the doing the build up repair technique instead of cutting it off and replacing it. which actually can induce far less stress into the spindle than one who has never done one would believe. However after seeing the picture I feel that he will be better off cutting the spindle off whether or not the rear end is removed from the vehicle to make the repair will have to rest on his confidence to make a proper weld in place. for me it would be a moot question I've spent more than my share of time at the 6 o'clock position welding on a critical part under heavy equipment, that sucker would be drug out from under the truck and placed on waist high stands where I could get to it easy and would probably even roll it as I welded it. I'd have that thing cut apart then either repair and machine the spindle back to new then return it to the housing, or preferably replace the spindle with a donated spindle if one could be had,a have it ready for someone to put the rear end back under the truck with my number stamped on the tube near the weld. Again as you stated it does take a particular skill set, and there will never be a replacement for experience. Until they have done a task for themselves all of the training in the world is nothing more than a base guideline.