The good thing about not knowing what you're trying to achieve is you will inevitably achieve it. Combining the two yeasts should give something like a bland hefeweizen or a badly fermented American wheat, depending on which yeast is more vigorous. At the pitch rates we use, neither yeast will completely out-compete the other before both run out of food and go dormant. Over several generations that might happen, that's why it's not recommended to pitch blends forward. I'd start with an idea of what I wanted from the beer, then make a guess as to how to achieve it. If blending yeast were a possible way of doing what I needed to do, I might try it. But never without an idea of what I was trying to do.