Wait, you ran it parallel for 3 years?

Standard newsprint or tabloid sizes" is close but not quite right for most Fillmore era stuff. Those were usually printed on heavy card stock, not thin newsprint. Think more like a thick postcard, maybe 14x22 at the biggest, but a lot of them were even smaller, like 11x17. The reason they're small is they were meant to be handed out on the street or tacked up in record shops, not plastered on billboards. If you find an actual 1974 Dead poster in that size, it's probably a handbill version, which they made for free distribution at head shops and such. The full sized posters were a bit bigger, but still never billboard huge. Either way, cool find, just don't go thinking it's the same print run as the big ones people frame today.