This is me again, good evening

In other words have to get dimensions one by one  manually and this 24 times 

as in picture bellow. Is this another way to get this spending less time ?

Am I on the right way ? doing this (by hand), instead you'll have something to show me and not using my old fashioned (may be) method.

Again, why the system setup wich is in in fractions, come in decimals?. Where do I have to look for this?

thank you