grid operations - select, copy, move

I am having difficulty performing operations on grids. I am not much of a JavaScript person (beginner at best) whose experience in web based Java applications using Struts, custom taglibs, and JSF.
Most of the examples and documentation are based on static data sources - our data is retrieved via Ajax calls to a Java server action class returning a DOM XML document in memory. The grid save (after edits) is also sending the DOM XML document directly to a Java server action class. We have no client side "var" data sources - all data is within the grid is loaded from the DOM XML doc using the table.setXML(req.responseXML) call in the response to the url (referrencing the Java action class) with XPATH AW Grid column info.

1) Can one perform all operations (moves, copies, edits, etc) on the grids themselves or must one "export" the grid data to local (client side arrays) vars and then perform operations on these arrays?

2) What is the practical limit of rows the grid can handle for reasonable load times and sorting operations? I realize this will depend on the size of the rows, so lets assume 4 or 5 columns of 25 chars for each columns (ie row size of 120 chars)?

3) Is there a specific documentation/examples for grid row manipulation?

Any help on this would be appreciated