Well, traditionally people used longer cranks for taller people... I've read a couple of articles saying that this no longer holds, I didn't know that...

Is anyone running SRAM S975 cranks with SRAM Red chainrings with Di2 FD? Should it work? Flawlessly?

I have already discarded buying the Mercury spider (with Red 2012 crankset + rings) based largely on price, but if old Red chainrings + S975 cranks work FINE with Di2 I think I won't be able to hold the trigger any longer...