0-5% nitro should work fine in that engine, what ever is cheeper over there. When you change to fuel with a different nitro %, you have to adjust the needle. All synthetic fuel should be fine, since it has ball-bearings instead of a bushing, like the 40la. When you are using fuel with no nitro, you shold be careful not to lean it out too much, especially with all-synthetic.Sometimes with no-nitro fuel, it is a little tougher to get dialed-in. Castor offers a little more protection in case of a lean run, so that should be fine too.