So today I did a 32 mile ride with a mix of flats and climbing. I actually tried staying out of saddle the majority of the time on the climbs, only sitting to give my legs a quick break. A few things I noticed. When climbing out of saddle I stayed mostly in low gear and climbing actually became easier. My heart rate stayed lower as well. I always used my OOS for high gear climbing, but I never thought to use OOS for low gear and for cadence control! The down side is that it's definitely more physically demanding, I had to shift my OOS positioning to utilize different leg muscles and also adjust my back and position over the bars. I think the fact that I was strength training prior to taking up cycling serious again, has made a difference. I also find riding my OOS style beneficial for sprinting as well, as I could easily clock up my speed while on the flats, but that's a topic for another post!
Thanks so far for all the info and insight!