I need advice on the best or most efficient way to organize charts in a workbook.

I'm designing a report that has 2 series of 25 graphs (results in a 50 page report with one chart per page). Currently I'm using 2 worksheets, one for each series of graphs. I like this strategy because it simplifies printing. The disadvantage is that it seems to take longer to update calculations when data changes.

Is there a limit to how many charts I should put in one worksheet, or a more efficient way to organize multiple charts?