I know I'm not going to get back nonexistent shadow detail, contrast and grain will be higher (grain? from Efke 25 in medium format? that'll be interesting to see)---I've done plenty of experiments in pushing film and I'm not laboring under any illusions that it's magic. But the roll is already shot and there it is; fortunately I think the subject matter may work well with the look of pushed film.
And I appreciate the offer of Rodinal, I know the people who love it love it, but I probably have too many different developers around already.
If it turns out that this really is terra incognita, I'll shoot a test roll in similar lighting and try it at 12:30 as a starting point.