Sorry, I misspoke. The strips that were published after TWOK were still set before TWOK (with the assumption being that the uniforms were adopted some time before the movie). The first two stories with TWOK-era uniforms, written by Martin Pasko, still reflect the standard command structure with Kirk as captain and Spock as first officer (though Kirk is referred to as "admiral" toward the end of the second storyline). But the last batch of stories, by Gerry Conway, take place in a time when Kirk is an admiral and Spock is Captain of the Enterprise. The first Conway story has Starfleet asking Kirk to temporarily resume command for a mission only he can handle. However, Kirk remains in command of the E for the next two storylines before Starfleet reassigns him to shore duty in the penultimate storyline. The final storyline, though, was an odd one that's hard to pin down in the chronology; Kirk is still in command of the ship without explanation. Aside from that, though, Conway's intent is clearly to show the events leading up to TWOK.
So basically the way I'd break down the chronology of the US comic strip is something like this:
ST:TMP: 2273
Comic strip storylines 1-13: First year or so of new 5-year mission, 2273-4
Uniforms changed: Sometime during 5YM
Comic strip storylines 14-15: Late in 5YM, maybe 2277
5YM ends; Kirk returns to Admiralty; Spock promoted to captain: 2278
Comic strip storylines 16-20: early 2280s
TWOK: 2285