Duo Aqua Oils are the best. I have not tried using fast drying medium. Let's see if someone else can add something to your question.
If you are using Duo Aqua with Walnut oil, then please do ask, I would gladly give you pointers and what to do and what to avoid. But nothing can beat trying it for yourself.
Good Luck! and we would love to see some of your work.
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