Your hair sounds GORGEOUS!!

I am soooo envious. I have never had hair down to my butt. Shoot, I've never even had it past my bra strap. My hair grows really really slow plus it's thin as ever.
I don't know if there really is a rule to the amount one is to wash their own hair. I think everybody has different hair types. Dry, oily, etc. Now mine MUST be washed daily. But again, it's thin and tends to be on the oily side.
I would think maybe just to wash as often that works for your hair.

I leave my conditioner on for longer than a minute but that's only because I abuse it horribly. I blow dry daily plus get colors on my hair. Such a No-No I realize but well it's a must for my head. LOL
And I've never heard of the conditioner you mentioned. I switch around my shampoo's & conditioners often. I buy accordingly to what I am in the mood for, LOL or what seems to smell really great.
For me, I have found that expensive products not neccessarily work better than the cheaper products.
But if you find some magic stuff, please do tell us.