Just look at the following benchmarks
- Human Surface area 1.5sqm or about 15sqft (includes head, neck, and extra space for flexibility).
- Surface are for just clothing (exposing extremities like head, hands, feet) 1sqm or 10sqft
- Torso is about 0.5sqm or 6sqft to get the full suit just x3. (the wife and my mother sews, and I got some sewing books) It takes as much material to sew a jacket as pants. It takes almost as much material to sew long sleeves as to sew a vest (but who wears vests?)
- Weight of a Full Space (Orlan Space Suit 130-250lbs or 60kg to 120kg)
- Weight of a Full Plate 60lbs or 27kgs
with the given surface area you can work backwards from various historical benchmarks
Sq-Cubed rule thingy magic. Increase the size by double increase the weigh by x8-x10 or increase the size by 50% x2.8-x3 the weight.
Cost is about the Infrastructure and Economy
Cutting edge 2MB was millions when it was first introduced and now just $20 and you can get 32GB flash disk (then there is resitive ram that promises Terrabyte flashdisks) Platearmor was about the cost of fair's ransom or about 20-30% a knights annual revenues, but with machining tools as cheap and available a full suit can built at a fraction of what it used to cost counting inflation.
Cost of a pinnacle dragon scale ballistic armor is around $5k (if you make it full body its going to be around $15k)
Cost of a Space Suit in their era is about $2M but mass produced and an economy geared towards the use of this would make its cost go down. pretty much the value of a car and all as much variety, with standards, and common features.
Same rules can be used to make armor, clothing, and life support suits.