Is there any way you can fill in the missing centers on each side? I think they would look better that way. I know this works on void cube mods, but I don't know if it would work on the "holey" mechanism.
The only reason this is called "holey" is because Lee Tutt (the original inventor of this puzzle) called it that. It is a true void puzzle.
And if you were to fill in the holes, that pretty much defeats the whole point of the puzzle, which is that it has no center piece.