You can only change shapes on the current slide or, if they inherit their properties from placeholders on the master, by modifying the master or layout that controls them.
So, for instance, if your charts are in content placeholders, then changing the size/location of the placeholder on the slide layout should get you there.
Otherwise, it's one at a time. Having to match up the size/pos of shapes from one slide to the next is so common that a little routine to do it was one of the first macros I ever wrote. I've long since incorporated it into the free version of a PowerPoint add-in that includes it and other useful tools
It's called the PPTools StarterSet, available at http://www.pptools.com/starterset/
It'd allow you to pick up and "memorize" the size/pos of one chart and then apply the same size/pos to any other charts with a single click.
[Update} The tool I referred to above is only only of the tools in StarterSet, which is still available. I've just spun this particular tool off as a standalone that now installs on the Ribbon (and can be customized onto other parts of the ribbon or QAT), is 32-and 64-bit compatible, and has a few other improvements and bug-fixes. Still free. Available here: pptools.com/free/index.html