jimc..... I think I will try Davo's sandpaper trick first as I have heard it is pretty much hit or miss with garolite plate. I think I can get 220 grit sandpaper with peel & stick adhesive on the back and lay on my glass plate. It's sounds like a great idea to try.

I noticed Taulman recommended a higher 245° C extruder temperature for nylon 618. I thought nylon has a higher melting point than ABS. Since posting, I found this on Taulman site
http://taulman3d.com/618-features.html

And this on Thingiverse site
http://www.thingiverse.com/thing:34801/#instructions

Are we talking about a different type of nylon? ..maybe nylon 645? Have you tried that setting with success or is that not a good idea?

Also, thank you for your advice on the retraction settings.