Thank you for all the replies and helpful information. After my original post I tried the search function on the site and came up with this very helpful post from last year by Ray, EC KS.

This has been very useful and another example of the benefits of this site. Thank you.

It appears that lightning rods tend to reduce the charge on the structure rather than providing a direct point for the lightning to hit....

Since this will likely be a steel roofed building, I will run a heavy copper wire all around the roof attached at several points and then grounded to several ground rods.

Judging by recent history the likelihood this building will get hit by lightning at least once a year or so is very high and worth the expense to set up this type of system. Basically it looks like the object is to make the roof look as neutral/grounded as possible. I may also add a couple rods at the peaks attached to the same ground system just for good measure.

Thanks again to everyone who replied and Ray.

Jim at Dawn