Excellent report Mark. It certainly sounds like you got a lot out of the course, even if it wasn't the skills that you expected. It is amazing how just a small change in kit configuration can send everything to ratshit if you're not comfortable with it. I remember one particular dive I did where I had changed my setup and something wasn't quite right and I kept rotating round to the left. Dealing with this occupied my whole dive and I hated it!
I wouldn't beat yourself up about the taskloading either. Dealing with multiple problems is something that most people can't deal with. However the experienced DIR divers are used to (for example) clipping off the long hose so it doesn't feature in their task loading. I'm sure if you asked them to do something that they're not used to (putting up a DSMBi?
) then they would not be perfect first time either. Practice makes perfect etc.
If I were King of DIR, then I would make fundies into two-parts: A definite two-day course followed a few weeks later by a clear two-day exam. The exam is often an identical copy of the course, except with no instruction - just assessment. BSAC do this with some of their instructor course / exams and it works really well as you know exactly what to expect.
Anyway, I'm sure with a bit of practice you'll have it sorted.
Janos