militarymonark,
It is super cool your learning to build wheels, not a lot of people step up to the plate on a skill like this. I watched all your videos, cool that your helping others learn the art. I noticed a few things while watching you lace up this wheel.
It looks like your not crossing your outbound spokes under the final intersecting spoke. 3 cross should go Over, Over, Under. 4 Cross should go Over, Over, Over, Under. The cross is what really adds stiffness to wheel, very important on coaster brake wheels
Also, not required, but definitely helpful, try to have your inbound spokes on opposing flanges going opposite directions, otherwise your wheel is biased toward drive direction or the opposite of drive direction.
Last thing, try to line up your valve hole to it is not in the middle of two intersecting spokes, this makes it easier to access the valve when inflating you tubes and makes everything much cleaner in general.
Sheldon Brown's key spoke method is the best when it comes to lacing wheels, also a try to match relative spoke tension before worrying about truing, old steel balloner rims are pretty stiff and can be deceptively straight before adding tension on the spokes.
All of these suggestions are just that, suggestions, I have seen plenty of stock wheels that were not laced the way I described and held up just fine over the years, however, I have destroyed ALOT of coaster brake rear wheels and would rather just build something stiff and strong from the get go.
And where the heck did you find that old Park truing stand? That thing looks early, I've never seen one like that and now I am very jealous.
Hope this helps.
-AJ