Hey Paul (correct name)?
The polyphaser company really does have great information on this sort of stuff. That's their business. Years ago, I bought a book from them called, "The Grounds of Lightning and EMF protection". Wish I still had it, but it's long gone. Anyway, TONS of great information in that relatively small book on all facets of lightning protection. I bought it to become better informed in protecting ham radio installations - mostly my own. The old falicy that you can't protect yourself from a direct lightning strike is totally false. These follks show in detailed ways you CAN survive direct (or close) strikes. Radio and TV broadcast towers all around the world get hit all the time, and they are still on-the-air!
The reason you don't want to use solder or tin any wires is simple. When these metals become part of a current path from a lightning strike, these metals will turn to water in an instant! They will not hold anything together and keep your equipment protected. The heat makes them melt quickly. That's why cadwelding (exothermic welding) is the preferred method of connecting wires to metal rods.
Cadwelding only takes about 5 seconds to complete, and is fun to watch. It literally welds the metals and ground rods together as one solid piece of metal. Large amounts of current from a lightning strike will not make them separate. No need to use hose clamps, screw-down lugs or grounding blocks, etc!
Finally, I'm not sure, and I wish I had this book for the answer, but you should steer clear of stranded wire for lightning protection and use a larger guage of solid wire instead. When I've seen others doing this type of work, they always use solid wire. Don't fall into the trap of using stranded because it's easier to work with. Use what does the best job.
The reason you don't find anything about solder on the polyphaser site should be obvious now.