I have yet to overhand cast with a two handed rod but I'm all about lessons. Sounds like you had a very productive day and found technique that can be put to good use. What's interesting is that you mention the little effort put into the overhead casting and the incredible results. That sounds ideal for fishing from a shore.
I'm relatively new to two handed casting but it reminded me of a Goran Anderson video describing the underhand technique. What impressed me was the seemingly small range of movement with and good distance. At the end of the video he mentions that he doesn't always have room to overhand cast. Different casts yes but it's a short and entertaining video from a great caster.
Sorry for the thread derailment, glad to hear you had a super day!
Rip, I saw a snippet of that and have been meaning to try to find that video to watch. Thanks for bringing that up as it's a good reminder for me.