From a meteorological stand point to me it don't matter..Lightning is what lightning is..
It will happen in a series of strokes..first a channel from the cloud to your mast(leader stroke),then you have a return stroke(return streamer) up the channel from the mast(this is the bright flash you see)..
Aluminum would transfer the load and heat better and more efficiently than carbon fiber...
I can see where the heat from lightning could delaminate carbon fiber...
no matter what mast you have you are the tallest object
..
thats the ODDS that matter!