Jim, thanks. I have considered using white space for a comma in the first line even before your comment. It has considerable advantages. It also, at least for the moment, feels wrong. Similarly for the couplets—making it compact feels wrong. I couldn't give an explicit justification for why, but I trust the feeling.
Mark, thanks for your comments and your suggestion regarding the quasi-line break in S4L2. I kinda like it, but not enough to pull the trigger just now; need to sit on it and see how it feels.
Roger, thanks. No need to be surprised: it has been claimed. I got it from Scotland; it means a drizzly, misting rain, the sort that likes to sit on Pittsburgh (where this poem was written) for days at a time. "Smir" may be a more common spelling. But it is not a coinage, much as I wish it was.
Matt, thanks for pushing back. We've disagreed about commas before, and undoubtedly will again. We have, I think, basically different philosophies of punctuation, and of commas specifically. My view is that (at least in poetry) commas are required only if the sentence cannot parse without them; if the sentence can parse without them, they are to be inserted only where a pause is wanted. In this case, the only options are two commas or no commas; the one comma option inserts a pause I don't want and fucks up the grammar. You are right that the reader must deduce which of the two possible readings I intend. I think it's an easy deduction, since one parses to produce sense, and one does not. Hence why I think the commas are optional, and why the need to avoid any post-'sodden' pauses is paramount.
I hope it's clear that in reacting strongly against your suggestion here I'm not at all trying to suggest that I'm not glad to hear it (and would like to hear it again the next time you find my punctuation choices frustrating). The last time we disagreed, you did in the end win me over (though after the poem slid down on here, so you wouldn't have seen it). But, in this instance, I'm afraid the task of convincing me is a hopeless one. There's just no way I'm putting a comma anywhere after the first line. I'll lose as many readers as I have to to avoid losing the poem.