Put the same mods on the base and prime version
The difference?
75 shields
75 armor
0.05 Sprint speed
Amounts so high that even a a beginning player can see that the difference is so small that it doesn't matter
However let's try it your way and see what happen when I actually put on armor, shield and a Sprint speed mod
So the values on ash will be
209 armor with steel fiber
292 armor with all umbral mods
740 shields with redirection
1.49 Sprint speed with rush
The values on ash prime will be
367 armor with steel fiber
511 armor with all umbral mods
925 shields with redirection
1.56 Sprint speed with rush
Well the difference is numbers is so small that it is funny.