The fuel I use is Cool Power 30%. I'm not sure if it's 4 stroke or not. But it is the fuel most recommended by YS. Don't believe it when it says not to touch the regulator. If it doesn't idle well, it's the regulator. But leave it where it is for now. May be perfect. Yes, I use two fuel filters. Watch the fuel line hook up diagram very carefully. It is correct but can be deceiving. Make certain you hook the lines up exactly as the diagram shows. It's very easy to get wrong (backwards) if you are careless. For 3D the recommended props are wrong. Again, 16x6 is teh best all around prop. The 16x4W is not enough prop. You'll overspeed the engine. I use that prop on my Saito 100. The other prop I use is a 17x4W. It will turn about 9800 which is more than the 16x6 but spool up is slower and thrust is about 1 pound less. But the 17x4W is way easier to hover with for some reason. But overall the 16x6 is the best choice.
Good luck and
Thanks
Barry