I shared some emails with him a year ago or so when I was learning about SHS design. Make sure to read his book. It would be a good subject for a young enterprising astronomer to take up and write a new book. Fred's manuscript is typewritten and therefore is hard to update with easier ways of explaining things. If his book is no longer online let me know and I can email you a copy. Much of the SHS information seems to be at risk of disappearing from the net.