I just finished formatting a paper to meet IEEE CDC 18 format requirements: first page has 74pt top margin, 54pt all other margins. Second page and beyond use 54pt margins all around. Note that the "margin" here includes the placement of the page number in the head, so the header offset needs to be added to the top margin in Document > Settings... > Page Margins.
What I wound up doing, is creating a document with the margins for all pages set to 84pt top, 54pt everything else (12pt header offset). I then made a second document with 66pt top margins, 54pt everything else (same offset), and a page break inserted to make sure the second page in the second document starts on the same line as the first document. I then deleted all but the first page of document one and appended the remaining pages from the second document to get a result that was compliant with the margin standards (they won't accept it otherwise).
This seems like a cludgy way to do something that should be easy to set up in either my layout file in Lyx or in the .cls file my layout is based off of. How do I set this up so in the future it is less hassle?