There are 3 10mm nuts per tail light (4 tail lights) that hold the tail lights from the inside, and the bulbs just come out after you twist them counter-clockwise. When they're out, just go over them evenly with the spray. Wait for them to dry, and then go again. Sanding is probably necessary, but I didn't really see much of a difference between some of the middle coats. Just don't drive or shut your trunk with the bulbs hanging like that. I went a bit too dark on my lights, so I had to get extra-bright bulbs to have the lights show enough. Perhaps this might be a bit too much, but it'* basically something to consider if you want tinted lights.
Also, someone else on this forum could tint some forum for you, and you could just swap out your other housings when the new ones arrive in the mail. I'm open for business if I can find some SSEi tail lights in a junk yard. I'll let you know, but check around.
94 STEi and 99 SLO