Hi there, I'd be grateful if anyone could please tell me what size band-on front derailleur I require for my 753 frame (SB7953). (I've become a bit paranoid about sizes, after my seatpost experiences). Are there any lightweight front mechs thats anyone can recommend ? Will a modern mech such as the SRAM Rival or SRAM RED do the job ? (It would be for a double chainset). Thank you for any advice.