i think GM should compare between orginal armors and weapons
for example the deferance between G50-G60 armor is 5 Def each part
make the deferace between G60-G70 is 5 Def
means if G50 chest has 30 Def, G60 has 40 def, G70 50 Def, G80 60 Def
and also do that with the wepons
and you will have a balanced armors just douple stats