For muscle growth, you can drink the metamorphosis potion. An increase in some muscles adds +1 parameter Strength.
About the limit armor, I'm not sure (if I understood you correctly), because I would like to have the opportunity for a male and female character to wear any clothes for more Customization.
I think it would be possible to add limit on the parameters. For example, if there is little parameter Strength, you cannot wear heavy armor.