So as I'm looking to get into 4x5, I'm looking to get a filter set. I'm only really going to be doing black and white photography, so just a basic contrast control set. I've seen that Kodak Wratten filters are a little expensive, so is there any brand I should be looking at? Do any of you shooters find square filters or screw in filters to be better? If I go with square filters, of any type, what holder is best for them?