nice!
LS9BLUEDEVIL I would make the base and then add the detail with 2mm foam and strapping. To make the templates for the smaller detail lines and stuff, the easiest way is to build the base, cover it in painters tape and draw the details on it. then just transfer the tape to foam and cut it out. painters tape is better for this then masking tape because the glue on masking tape is stickier and could wreck the foam. if you only have masking tape you can stick it to your jeans and then use it. just to remove some of the stickiness.
that's how I did the front of my Osiris chestplate:
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