how do you measure the upper leg pieces for scaling

[firebapx]

making my iron man suite and im not sure how i should go about measuring my self to make my upper legs pieces i need to know so i can recalculate the parts size in pepekura. i made war machine armour before and my upper leg parts where so wide they just looked rediculas could you guys please help me know what park of my self to measure

 

[rensole]

measure the part the piece is going to cover? thats how i did it.
just keep making and scaling it till you perfect it