So I forgot yesterday was a public holiday. The sodablaster wasn't open until today. And gosh am I tired. My back aches, my fingers feels like they're under rigor mortis, and I think I've ingested way too much aluminium particles. But I got it all polished up. And I'm completely drained. Here are some pics. I'm not gonna bother explaining what I did in each step, a brief caption will do.
Back from the powdercoaters. Note the surface:

My working area:

Comparison of lips. After 240 grit sanding vs. raw sodablast.

Close-up of post-240 grit sanding:

Close-up of post-600 grit sanding:

Close-up of post-1500 grit sanding:

I sanded from 240 grit, then moved on to 400, 600, 800, 1000, 1500 and finally 2000.
This was after polishing with black and white compound. Note the smudging:

And finally, finished it off with Mothers Mag Polish:

Comparison of lips. Raw sodablast vs. fully polished:

Far from perfect, but time was against me. I spent too little time with sandpaper grit 240 and 400, hence the leftover scratches you can see between the bolt holes, and the rough spots where the lip bends.
Anyway, tomorrow I do the wheel stands. Hopefully I can get Dad to help me out!