WoW, tell me your going to hire this rig out to run those big a$$ screens at a U2 concert!
If 1x2 is good how does 2x4 stack up when playing games?

Looks good mate, now strip them down to there nickers and dress them up for the concert.

When do you expect to get the blocks nickel plated?

If you not sure about the look of grub screws, the only other idea I have would be some black vinyl film, might be too high gloss but, hay black insulation tape is a matt black, I am sure you will find something.
You may still need to fill the holes up with somthing still (eg grub screws, putty) to stop the film from showing up the holes underneath.
As it will/may look like the side of the SSDs has 2 small dents where the holes are underneath.

Keep up the good work mate.