Hello there?
Am a professional accountant as well.
From your explanation, it's not clear whether it is an entire hand material or just the arm (At one point you talk of the hand and the picture is just that and at another you mention up to shoulder).
Secondly, you need to consider the average size you will be working with since that could alter the material each time.
Third, when you are sure of the size, consider the size of the chips on each arm/hand and the zetix fabric in each case. Find their cost in the market you are working with (UK/France/Germany), it may vary with the place.
Fourth, that will enable you come up with the cost of material per hand/arm.
Good luck:)