Hello foxbabby , 

Thank you for posting in our forum. 

You cannot set the tooltip size but you can change the text by changing the tooltips format strings.

The in-built format strings you can use for the tooltips are the ones described in our documentation under the TooltipStyle:

http://help.infragistics.com/NetAdvantage/ASPNET/2011.1/CLR4.0/?page=Chart_Use_Predefined_and_Custom_Label_Styles.html 

You can also set up and create a custom one as is described also in that link.I’ve prepared a sample with setting a custom format string for the tooltips of a pie chart. In it I set the item label and data value for the text of all tooltips except the one for the “Others” segment. Please refer to it and let me know if you have any questions or concerns. 

Best Regards,

Maya Kirova

Developer Support Engineer