I should at least contribute a review on using synthetic 5W-30 engine oil.
It is VERY hard. There is hardly any dive on the front forks, and hitting some rough roads at low speeds is almost unbearable.
I've driven lowered cars with "sport" suspension, and rode a variety of motorcycles. I could compare it to a rigid frame chopper of sorts, almost no dampening action.
I am switching to fork oil when I get a chance!