Alternative way to mountain 36T sprocket



I got tired of my spoke-mounted sprocket, after three tries i was never able to get it perfectly centered. So here is what I am looking at doing.

I have a spare rear wheel that has a disc brake mount on the left hand (sprocket) side.

So i am going to try enlarge the hole on the sprocket so that it can fit around the disc mount, then bolt the disc rotor to the sprocket through newly drilled holes on the sprocket and existing holes on the rotor.

Then, i will mount the disc brake rotor back on with the sprocket on the inside, nearest to the wheel, to provide proper alignment.

Does this sound like a good idea?
Grubee has a heavy duty rear axel assy that I really like, but I am confuse about ordering from them.

Tried to insert web page but it wouldn't go to the right page.