OK... I looked up the data I recorded on string weights for my warbows. Two strings, both 74" long, one 14 strand, one 20 strand. D97 FF. That's waxed and ready to go, both with an 8" long X 0.24" diameter serving.
14 strand string... 131 grains
20 strand string... 146 grains
You do the math. It's nothing. I found it makes more of a difference what type and size of center serving I used and how much and what type of wax I used on the string that made the biggest difference! I had some 20 strand strings that actually weighed LESS than some 14 strand strings, because I used a smaller diameter serving and less of it.