If I could offer some words on this gentlemen as I have a little experience with this. The pic in the first picture is a "unitised plotting disc" These can be had from many makers and are often peddled as "gasket removing discs." They come in many grades and colour indicates grade. From the ones I have used brown is the coarsest, then red, and white (greyish white) as shown. They come in 2" or 3" and the adapter shown is for a drill or barrel grinder. The rubber backing pad on mine unscrews and I have another arbour so I can use it on the 4" grinder ( my weapon of choice). I do not use any cutting compound on these. For aluminium I would start with the white and be careful not to take too much off and not to let too much heat build up.
The rogue (or wax) and mops are a different polishing system. The mops screw onto an arbour that is tapered with a coarse thread that screws into the centre of the mop. Some of the smaller kist sold by buntings and super cheap (I think) come with an arbour to go in a drill that is really nothing more than a bolt.
There are 3 kinds of polishing mops commonly used. The sisal is material with sisal rope in it to make a coarse cut, the next is a stitched mop which is linen that is stitched so when you lean the workpiece into it the mop holds it's shape. Lastly is the rag mop which is just cloth and only stitched around the centre.
The cutting compound is colour coded to how hard it cuts. There are loads of colours but generally brown is course if needed then green and if you want a high lustre finish on aluminium or stainless go to the white. In an ideal world you would have one mop per colour. If your going to use a bench grinder which is my preference then I'd suggest an 8" and preferably 3000 rpm or a bit less. After a bit of polishing you'll get covered in fluff and waxy rogue. You should wear a dust mask and face shield. Ideally.
