Well, the people who are going to refinish and paint this said that they were intrigued by it so I figured I'd hand it off to them and they can fix it better than I can especially considering that I don't have the right equipment to do so.

My 100w SDW-T ballast makes some nice growly noises during startup. First time i turned it on, i thought something was going very wrong. But that goes away after only seconds.

Nice! More 400W fixtures! I have two thorn MBI-400's I need to finish up one day. They both have dead igniters. I have replacements. Just haven't had the time to fix them yet. I have a new old stock reflector so I'll be able to make one of them pristine, the other will... Look a bit meh. But they will both work! Massive power users, but they're extremely cool and no amount of other lamp technology comes close to how impressive I think these big things are! I have a few spare lamps but not a huge amount. They last a decent number of hours, but they're driven really hard!

I've seen Philips SDW-TG 100W rectifies for long on an electronic ballast: https://www.lighting-gallery.net/gallery/displayimage.php?pos=-251959

@James  noted that SDW(-T) electrodes are just straight rhodium-tungesten rods, without familiar starting aid coils. That means these lamps are expected to be quite hesitant with glow-to-arc, until electrodes and arctube become hot enough.

SDW(-T) lamps actually glow-to-arc somewhat faster when on squarewave electronic gear.

We have a storm of rain: https://www.youtube.com/watch?v=cl1da9rYFeo
And it is 16*C now.

It takes patience, and practice. Prep work also helps significantly.
I was horrible with spray painting (I used to refurbish traffic signals as a side gig), but I learned and got techniques from other collectors. Nowadays I’m more comfortable and do far better work. It’s not a 1 day job, it’s something that could take up to a week.

There’s a vid on YouTube of someone restoring a OV-15, and what that individual did is very similar to how I’d approach your fixture, minus maybe the little details, like filing the craters in the mold.

A subjective option could be leaving it as-is. A good cleaning with Simple Green and water goes a long way. Not to mention you’ll never get that factory Westy paint again, even if it was professionally done.

Yeah but I've tried different hammertone paints already and they don't show the hammertone look nor do I have prior painting experience.

Powder-coating is very expensive, and you’d have to find a vendor who would be willing to do something on the novelty side. Not to mention if you get a scratch or some damage to the fixture (which will happen, wear and tear), it is very difficult to correct.

A more logical and cost-effective option is to use the regular off-the-shelf spray paint. @BT25 has good experience doing this with his Silverliner. It’s easier, less expensive, and easy to correct if there’s imperfections or you get any sort of surface damage to the paint.

Yup, early troffers were listed in catalogues as early as the 1940s, typically looking like modern 1x4 troffers but with deeper housings and glass instead of plastic. In some cases they were open or had louvers.
Rest-Glow
Curtis Lighting
Day-Brite 1941
Day-Brite 1947

At the time, most installations using troffers arranged them in long continuous rows and were 1-2 lamps per cross section although a few 4 lamp models were available. Fluorescent luminaires was still a mix between recessed troffers and surface mounted types such as half pipers and louvered fixtures. Various models were made, including ones for long extinct lamp types such as F90T17. These of course were predominately preheat, rapid start would not be introduced until the 1950s. Most building ceilings at the time were typically wire lath and plaster or 1x1 tiled so in most cases troffers were a lot harder to install compared to surface mounted luminaires.   

Modern T-bar ceilings were only patented in 1958 before then tiled ceilings were typically attached using furring strips with screws, adhered on, or was a removable system where the tiles needed to be removed sequentially. The 2x4 troffers designed to fit into a T bar ceiling probably came out in the late 50s as well. By 1960 troffers resembling modern 2x4 troffers were in catalogues.