paging is solely through the report, you cannot program that into the report.
What I mean is that you can write a formula to make a new page in the report, but I doubt you can do it from C#. Also there is no reliable way to do this unless you count the rows on the report (or you can use the size of each section on the report...same difference). But if you have a cell that 'Can Grow' turned on, all bets are off as CR does not tell the size of anything displayed, nor does it give you a way to determine what happened. You can guess at the size, but if you are proportional fonts, you don't even know how long it displays as, so counting lines is as good as any method.
As for setting the size, you might be able to do that from C# if you know the control name, I've never done it, so I am not positive that you can do this. The only caveat that comes to mind is that you multiply by 1440...if you want a section to be 1" tall, since CR uses twips, you would need to convert the 1" to 1440 twips.
HTH