the new Code:Reds will be setup to accept RDM option in the smaller (speed) sizes inc 4.6m/5.6m (these sizes are tuned to SDM Blue Line, masts not 100%RedLine anyway) . You will be able to use your RDMs doubling into wave use + also have the bonus of more bulletproof masts ~ in case of serious speed wipeouts
. RDM has a theoretical lower drag and usually tests better with acceleration but the rig at top end is potentially not quite as super stable as with SDM. With a softer sail setting the rider is less likely to be lifted with a big gust (sail/mast deforming more to absorb the gust impact - but at the same time becomeing abit less efficent etc). For the larger sizes, the RedLine SDM is a very important part of the extra performance (including the very precisely matched mast/luff curves).
Sleep easy at night. No worries.
Cheers ~ Ian