Ferrite beads can definitely help with EMI problems, especially at the high frequencies that tend to cause problems.
SMD will give you less parasitic capacitances and inductances, and yes, ferrite beads are available in SMD. Main problem is the difficulty for breadboarding and prototyping, but big SMD parts are very easy to work with.
Thanks, but which ferrite beads?? or does it not matter too much? I have a couple of toroidal shaped ferrites but they're about 20mm diameter although I could use just 1 and wrap each wire around opposite hallves.
And there's another question how many times does the wire need to be wrapped around the ferrite or just passed through it?