Sorry I didn't get your PM and meet up at sign in or lunch or something...maybe next time. :)
I agree with you on the 2-day vs 4-day thing...always take the 4-day. I made that determination when I took a 2-day shotgun class back in the day, because I had a certificate for only a 2 day class (before I had memberships).
As for the ropes/rappelling class, we really liked it. My GF wanted to take the class even though she is afraid of heights. I said I would do it too, to reinforce her interest in training, but I'm WAY afraid of heights too. I had a hard time climbing up the ladder to my 2nd story roof line to install a ham antenna not long ago.
Turns out though, since I'm so analytical in my thinking, that once I'm attached to a rope or zip line, I'm almost fearless. Probably only pushed a 4 or 5 on the o-shit-o-meter the first time up the 50' tower and maybe a 3 riding the zip line (first time for me riding a zip line ever).
The skills and knots given are well thought out, as all the FS classes are. It's somewhat physically demanding, but not overly so. My abs were sore by day 2 from "crunching" to keep upright on the rope while hanging from the rig.
We both graduated, but think we will go back and take the skill builder next year once it starts to warm back up, going for a DG in the class. :)