I have a rather nice romantic guitar that had 3 strings added. This was done by enlarging the bridge towards the bass side, and gluing an extra head for the additional strings onto the head. It was well done. Unfortunately it resulted in a spectacularly mediocre guitar.
I removed the bridge, a massive one, replaced it with a smaller, much lighter one, removed the extra string box, with very happy results.
I'm afraid that if you do this conversion to your guitar, you will get the same results.