jQuery Grid Plugin - jqGrid

In the example for loadonce option, you load 13 rows but show only 7.  I don't see any parameters that make this happen.

When I limit the height, it breaks down a row (I cannot calculate height exactly because my rows can have different heights) or creates empty space if the height is too big. If I set height to auto, it shows all loaded rows.

Basically, I need to show all rows when the table has fewer that, say, 10 rows, and then show only 10 rows and a scrollbar (no pager). I guess I can go with a pager and without loadonce, but it's not a huge table, so scrollbar will be much more convenient.

Any ideas?