"Do you have a pic of one with those $38 filters mounted in it? Does the filter fit completely inside the cone or does it portrude?"- Jpswino

 From the 3rd pic on post #21 you'll see the side with slits. that snaps onto your carbs. The filter slides on and butts up against the shoulder on the other side. Again I designed the stacks for this particular filter that has 75mm centers. I've made 3 different prototypes and this new one is the best so far.
  I can surely make them for your 29mm smoothbores just pm me with the throat diameter dimensions and I'll draw it up on AutoCAD and see if you like what you see. No commitments, no worries.