What would be a reasonable and appropriate substitute for the Stronglight 93 crankset on an early-70s Raleigh Gran Sport? I need low gears--either a wide-range double or a triple of some kind. A Cyclotouriste would be great, but would likely be way too spendy for me. I'm thinking of an Stronglight 99. What else might work? Of course, I could use any sort of modern crank, but I'd like to use something that's more or less period correct and looks right for the bike.