Add a few drops of water based food colouring if you need help seeing the separation. Make sure to use high octane of at least 91 octane as once you drain off the subsidized alcohol, it will drop it to around 87 octane. Great idea, love your efforts.
Most ODPE engines have very low octane requirements, especially the old flatty's with 6 or 7:1 static comp. Motorbilkes and ATVs likely need more than then the resultant 83 or 85 R+M/2
I only said it out of discretion as a warning. I don't know a whole lot about outdoor power equipment but I know I'd rather have the octane too high then too low especially in the summer. I haven't seen 85 octane since I lived in Casper Wyoming