I would also like some information about these questions.
For print centering I have resorted to de-selecting the "center image" check box in the PS CS3 print setup dialog and then, by trial and error, setting uneven margins to get the actual margins to be approximately even. An awkward thing is that it won't accept any setting (at least in inches) but shifts to something close but not exact.
1. Is there any way when printing on sheet paper to have the gloss optimizer top coat to have even margins around the image. It always seems to be longers along one side. The image seems to be centered (if you use big enough page margins) but the top coat is longer along one side resulting in an uncentered look.
2. For the life of me, I can't get an image centered . . .
Any advice would help. Thanks, JR