The vacuum frame should work fine and I assume it has a light source. Sometimes, very seldom actually, vacuum frames can cause an uneveness in Pt/Pd prints due to moisture retained in the paper. That moister gets forced out along the grooves that are typically found in the rubber pad that comes in the vacuum frame. A piece of matte board under the print, black if possible, will usually cure that problem. But, just try one and see what happens. It will more than likely work fine.