The system is coming along nicely! I wish I made more progress on my system so I can have you over.
I think you should stick to your original plan of housing a magnifica. You'll be much happier. Trust me! I'll keep an eye out.
One thing you'll need to change though -- you'll need to find a flat rock to place on top of your rock structure. Mags don't like porous rocks like pukani because they can't spread their foot out. I often describe it as looking like a fried egg because they try to expand their foot on the surface of the rock as much as possible. If you don't have a flat rock, they'll continuously move, and will eventually make it to the wall of the tank, which isn't visually appealing.