I bought an extra set of KTM guards and chopped off the wind deflector part, this makes the profile much smaller but does support the fron of the muffs and stops wind blast from pushing on the levers and your hands. This also keeps the muff off the back of the hands and consequently allows warm air to stay around your hands. During the winter once the heated grips have warmed up the bars I usually turn them DOWN despite the cold!
PS I have the cheap two stage setting hot grips which just have a rocker switch to operate them, simple and cheap, but effective.