Yes that looks good
A tip with that cage that someone on here did. When you're putting it together (it's flatpack), you can swap around the bottom front door with the top panel. This is better because it's pointless having a door at the bottom when you have at least 6" substrate in as it'll all fall out. Wherease a door higher up means you don't need to keep lifting the top lid off (and can have access to the hammy from the front).
For a robo and for safety, I would either
a) Only put the bottom shelf in, not the top one. So they can't fall from a height and bounce off something on the way down (they are tiny and can be seriously injured by falls).
b) If you intend to say put very deep substrate in, then leave out the bottom shelf and just keep the top shelf. Either way the robo can only fall off one shelf and land on substrate,
Personally I would go with a) because I don't think there is any need for say 40cm deep substrate and you might never find him! It would take a massive amount of substrate. Robos can easily tunnel in 6 to 8" of substrate. Ours used to pile it up in one area if he wanted to tunnel through it. It would need to be at least 40cm deep so there wasn't too big a gap between the substrate and the top shelf (again fall risks onto a house or something). Robos are ground dwellers really. They like a shelf though. I had our robos sand bath on my shelf (if it's heavy helps if it's on something solid).
More floor area is better than more height/extra levels, and safer. There is plenty of floor area with that cage, so I would leave the top shelf out.
Painting - it would take a lot of plastikote! With those little pots. For the inside I reckon for two coats it could take about 6 to 8 little pots at least. And maybe 4 to 6 for the outside (as you won't be painting underneath).
The important thing is to paint the floor inside so it doesn't get pee soaked.