I, too, have had to make some adjustments to be able to use WEN. I love its results, but I can't use it as my main shampoo alone due to scalp buildup. The same thing happens to my son, but not my daughter-in-law, so it may reflect our chemistry. I have found a solution for my mid-length, thick, wavy, color-treated hair that leaves it looking almost as good as the models' hair.
I use a shampoo by Loreal from my salon, intended to help keep color. It's not as good as WEN is for that purpose, but not as harsh as grocery store brands. It cleans my scalp well, though. (Which is not oily at all, just normal.)
Next, I use WEN Tea Tree shampoo/conditioner as a conditioner. I apply it as directed, working it into the hair shaft and leaving it on a few minutes, then rinsing really well. I actually rub the hair from scalp to ends to help it wash out and smooth my hair cuticle as I rinse.
I apply about 4-5 pumps as a leave in conditioner because my hair is fairly thick and tends to frizz a little along with the waves.
I use the styling product as well, combing it through with the great WEN comb. I am then able to get a beautifully smooth blow out with bounce and some curl.
However after two days, all around my face & hairline, the hair still tends to get limp and a little greasy-looking. (My skin isn't oily, but I do moisturize my face well.) Rather than start all over with the cleansing I can go a few more days by just washing lightly the hair around my face. I hold the rest back with a hair band & use a normal grocery store brand.
This may not be ideal for protecting color, but it's a good half-way for me. I love the feel of WEN & still want to use it!