This is the article you should read.
http://f1.grp.yahoofs.com/v1/sIfrRUQ...the%20LX90.txt
Also do a search in the group for people feedback on using the reccomended EP's. Note the one I mentioned before as a replacement to the 1rpd is 2" 30mm UW fro Clearvue. Do us this on a 8" you will need to get a 2" diagonal and you will get some vigneting, but for the price (same as the 1rpd) apparently the area you do see is far better than the 1rpd.
Regards