Completely irrelevant to the conversation, Richard, but... now, thanks to you, I'm going to have "(It was an) Itsy-bitsy, Teeny-Weeny Yellow-Polka-Dot Bikini" playing over in my head for the next few days... a tune I had (mercifully) completely forgotten....
*Harrumph!*
On topic... the font size isn't quite as small as many of their older books, no (and I sympathize, believe me!); but it isn't exactly an enormous size either. Still, it is more easily legible, and they are both attractive books and offer very good texts and excellent annotations, so you may want to hold onto them regardless....
No, Arkham House didn't release an errata list for the set, so far as I am aware; but then, so far as I can recall (I am sure someone here will correct me if I am wrong
) they have never done an errata list for any of their volumes... and some of them would have been the better for it (e.g., Hodgson's
The House on the Borderland and Other Novels).
Also, depending on how far you wish to take this, you might want to consider the Hippocampus volumes
From the Pest Zone, which collects together all the stories HPL wrote while living in New York; and
The Annotated Shadow Out of Time; and, if you can find a copy, Necronomicon Press' annotated edition of
The Shadow Over Innsmouth. Each of these contains supplementary material of considerable interest.
From the Pest Zone, for instance, has a fascinating lengthy introduction by David E. Schultz and S. T. Joshi, as well as information on and photographs of the locales concerned in the stories, a copy of the newspaper clipping of the little court off Perry Street which first caught HPL's eye and directed him to this locale (the site of "He"), Frank Belknap Long, Jr.'s "Preface to 'The Shunned House'", and copious annotations;
The Shadow Out of Time not only has the complete text of the story, but another lengthy introduction concerning its origin, convoluted publication history, and the history of the long-thought-lost manuscript from which the text is taken, as well as HPL's "Notes" to the story and an early draft and, again, copious annotations;
The Shadow Over Innsmouth features the usual annotations and introduction, HPL's notes to the story, a discarded draft of sections of the tale, etc.