You could also keep the cottered crank, remove the outer ring and replace replace the chainring bolts with 5mX10 bolts from the hardware store. If you buy a cotter press from Bikesmith Design and a few cotters, you'll surely end up spending less than you would converting to cotterless. Cottered cranks are cool, especially if they have Simplex adapters and rings. My chainline is dead on with a Formula hub and EAI cog.