Hi,
Thank you for posting your query to us.
The row and column height of a locked cell can be adjusted using the rowheight and column width properties.
I have created a sample based on this and it is available in the following link.
http://websamples.syncfusion.com/samples/XlsIO.Windows/F67525/main.htmPlease run the sample and let me know if this satisfies your requirement.
Regards,
Sarathi