One more consideration regarding clear fin units, for the very same reason, the motor mount tube will go through the center of the fin unit, so, it would distract from any rocket that you would build, there is no getting around that.

If a fin unit made of clear material could be attatched to the outside, say, of a scale model, that would work as long as the engines are part of the rocket, protruding engines that shouldn't be there will distract from the overall decor of the kit.

Many considerations that you need to keep in mind while designing rockets.