In lieu of a vaccum easel, I use a few long strips of double-sided masking tape on my 4-bladed easel whenever I print fiber. I "prime" it with lint to reduce the tackiness. Before printing, I place the paper as normal on the easel, then I press the print onto the tape with a cotton cloth. Then I blow off the print with compressed air that I have piped throughout the basement/garage area where my darkroom is. You must take care when "peeling" the print off, so you don't kink the paper, and it may take a few prints until the tape gets to the right balance between too sticky and not sticky enough. But I have found that doing this has eliminated any problems I was having with uneven sharpness corner to corner, especially when using older paper.