I did the paper mod on one of the pancake filters. I cut off the original bolt and then used a longer bolt of the same diameter. I added a nylon insert lock nut to keep the new bolt in place. The longer bolt is required because the filters that were available online were taller than the original wire mesh. I added an appropriate size wing nut on top. Pic attached.
I can't tell you if it affected performance, as I've never used it. The carb on the later 235 I'm going to use has the center stud, so I went with a later style filter. Sacrilege, I'm sure, but I always liked a snorkel style filter.
