In the "System" tab /tags, there is Execution and PUSage, i'm ASSUMING "Panel CPU Usage [%]" actually means the PLC CPU and not an HMI/Screen cpu usage.
But, i have not found any tags telling me how large my program is, but in the tech specs pdf, i found ladder memory is 1 MB.
Many customers requires data on how much free cpu and memory there is, and plenty require that atleast 20-25% should be free at delivery for possible future expansion.