and here was me doing a double split like Arnold 
Nearly ALL of the old-timers did full-body workouts in the 50s and 60s, even well into the 70s.
It was all about putting on pure size.
Now, full-body workouts have been reduced to mere use for beginners.
People make the mistake of training the way the pros do NOW, particularly when getting ready for a show, instead of training the way they did during their early years.
I remember profiles on one of my favorite bodybuilders, Mike Francois. He had an article which detailed what he did during his younger years vs. what he did as a pro (or national-level amateur). He either did full-body workouts or very simple splits with far fewer sets than he did as a pro. And off-season vs. pre contest were like night and day.
Arnold worked out with Reg Park maybe twice in his life.
However, for natties I believe full body is the way to go.
I did full-body for a year when I first started. Then, I tried various splits. I finally got the one the works best and it's the simplest. Upper body (Mondays and Thursdays), Legs and abs (Tuesdays and Fridays).