My 999S rear suspension was not at the factory standard settings when I bought it. Compression damping was about right, but rebound was wound up big time! It didn't unduly affect my handling, but it's worth making sure they are at the factory standard, to start with.
Also, make sure the tyres are correct make/size/pressures for the 749R.
Agree with Felix, probably not a steering damper issue at all.
749/999s seem susceptible to crosswinds (in my opinion) but this should manifest itself as a desire to change direction, not a weave or wobble.
My two cents (nearer three, probably)