I've never done very well with Mars, and my best views--never that good--have been with an aperture mask. With full aperture, I just get a red and white blob of chromatic aberration.
I had a 75mm single-hole aperture mask that I was planning to use in my 8" F/4.5 Coulter for solar projection, but tonight I added another hole to it. Both holes miss the two-vane spider. The views of Mars with the aperture mask and a 5mm ortho are great--best I've had. Two dark areas (one was probably Mare Acidalium) and a bit of polar cap. I don't know if they're better with two holes than with one--there may be better contrast with one--but they are a bit brighter with two, and I love the easy focusing (with the mask, you see double and you focus by merging the images).