I use half m-5 and half standard methanol. I havent done any back to back so I'm not sure there. Its very consistent for sure. I've used it for several years with good results. You dont want it too lean as it'll burn electrodes or pistons. My big w-8 SB made about 910 on the dyno. The smell is mostly tolerable as long as your headers point outward. Ive also built a primer plus system to save fuel on warm ups.