If eeprom size is enough then it makes sense to use it instead of an external storage.
The byte size depends on the variable type , for example
1 byte:
signed: -128 to 127
unsigned: 0 to 255
2 bytes
signed: -32768 to 32767
unsigned: 0 to 65535
4 bytes
signed: -2147483648 to 2147483647
unsigned: 0 to 4294967295
float +/- 3.4e +/- 38 (~7 digits)
and there is the object name which depends on what you have defined, how many char do you provide for the name, is it 10 chars , 20 chars...?