Don't forget fit and position. Are you farther forward and "down" on the Legend? Longer reach to the bars....more "racer". How much time will you have to dial in the Legend before the ride? Is the Saluki more of a cruiser...likes to go straight, takes less constant input to hold a line? Will a 39x27 be low enough after 80 miles, you're on a shallow but long climb or series of steep rollers and the legs are cramping and you're feeling the drum beat of low-grade bonk?
Generally, the Legend may be a beauty for you, but if you're planning your first century this fall and 50 or so is your longest ride so far, you may want a bike you're hand-in-glove accustomed to. Sustained comfort may be a goal this time over speed.
Besides, the Saluki is a fairly unique bike and others will want to admire it and chatting does pass the miles away.