You can do this with layout adjustment. Switch it off, set the margins
of all pages to be flush with the pdfs. Then switch it on. Check "allow
graphics to resize". Now set the margins to whatever size you want your
pdfs to be and they will resize.
It will still take a while for InDesign to do this to 1000+ pages, but
at least you can sit back and do nothing. But test the procedure on a
dozen pages or so first to make sure you've got it right. Also, make
sure that in the margins and columns dialog, switch preview off before
you make any changes to the margins, otherwise you'll have to wait × 4
for each change!
Ariel
![[Ariel]](/people/%5BAriel%5D/avatar/30.png?a=-1){kind=small}
