With a 35mm and the enlarger head of my D-II in its lowest position with a 50mm EL-Nikkor, it shines an image of about 7x10 onto my easel. Now, if I want to print something small like a 4x6 or 5x7, which would be the better method, to get the frame size down? Making a shim to prop up my beastly 4-blade easel to be closer to the lens, or just use the 135mm lens? Drawbacks/advantages of each method?