#6- None of the above...
What I'm suggesting is a plug that looks like just the body plug right end ONLY of 3, 4 or 5 and that will directly let you attach the vertical adapter from a regular size autococker so that it points forward. This would produce a tighter assembly and it should be stronger since it's not depending on that little stub of the 1/8 NPT.
Let me see if I can photoshop something up or just sort of place the stuff in place to show you and get a picture tonight.
The other option that I want to try is just run if from a 3.5 oz mounted bottom line style and then play with it tank forward and tank back to see which I like best. And then run a 48 round hopper up top.