I did a search after posting and ran across the focus issue on Robert Reeve's website....but he also said this:

"This is not as much of a problem with reflector telescopes, but it is a good idea to use the filter anyway to get a crisper focus."

Not sure why it may not be as much a problem on reflectors (which I have), nor am I sure just how much of a problem it would be to begin with. I know I do have some problems focusing on my f/5 scope, it probably would help...but I will wait a bit until I get this astrophotgraphy thing down a bit better