IMO If you were really worried a/b it besides the #1 safest practice (not going out), I'd say put a lightning dissipater on the top of your mast. They look like a little metal paint brush that's been "fluffed".
http://www.westmarine.com/webapp/wcs/sto...mp;classNum=776A class I took, Electro physics for Engineers dealt with this during a lecture. The professor brought in a Gauss generator and cranked it up. As it was (smooth round surface), it would discharge with a bolt/arc to a nearby grounded object because the smooth surface would allow a charge to build. He placed a paper "stake" (pointy thing you put papers on) on top of it and once the electricity had a sharp point to dissipate through it stopped arcing. The charge was being disipated through that point as a harmless invisible stream of electrons.
The lightning dissipaters do the same thing. Since lightning is a ground to cloud phenomenon by having this on top of a tall object it allows the charge to be put into the atmosphere and not accumulate and create the strong discharge, i.e. lightning.
