I'm trying to get a page counter so that the page number is displayed in the top left and top right of every page. However, if the top-left is 1, the top-right should be 2, followed by 3 and 4 on the next page, then 5 and 6, etc.

@page {
	@top-left {content: counter(page) string(doctitle);} /* 1 3 5 7 etc.*/
	@top-right {content: string(sectiontitle) counter(page)} /* 2 4 6 8 etc.*/
}

Is that possible? Thanks!

Two different page numbers on the same page is probably not possible at the moment, although it might be in the final release of Prince 8.0, where you could use JavaScript to return page+1.