I'm not really going to answer your question either because I don't know anything about mixing fuel. As far as I know Coolpower is ready to go out of the jug. If your talking about thinning it out with something else to stretch it out, then what are you spending your money on Coolpower for in the first place? I've used 10 & 15% nitro in my OS32 without any problems. I pay $16.00/gal for S&W 15%. I haven't noticed any real difference in power between brands. I think the bigger the name, the bigger the price. I don't know what's avail in Belgium but I would hope you have some alternatives.