I think most of it's been well covered before, and I'm no blasting expert by far (I've only stayed at a Holiday Inn), but I think it does come down to the surface prep and time on the blaster.

From what I've done with firearms preps for finishing and parkerizing, it can get to a point you miss something you thought you covered "enough". One of the other factors can be the feed/return of the material when you're blasting - spending time on an area but not getting the same volume of blasting material dispersing.

A little hand prep time with just some 400 grit and good medium and flow will probably be enough.

It looks nice though - especially for an intended user. Always a work in process.