I have to confess that power efficiency wasn't/isn't top of my list. As it happens the parts you suggest don't feature on the Farnell website which is where I did my selection. I use the L-1334SRT. I can't now remember quite how I chose it but I'd have been looking for some combination of brightness and cheapness and availability. I would be budgeting 10mA per LEDs as that's the kind of number I was used to, if it didn't want more than that then that was all I asked on the power side of things.