Hi Harb, filter usage and their visual effect is naturally very dependant on our own individual eyesight and biological perceptions, here is a link that tests some Lumicon filters against popular DSO's and it gives a feel for what might be suitable for each object, the author recognises that his perceptions may not be shared by others which is nice.
http://mysite.verizon.net/vzeed81b/f...rformance.html