[madscientist]

So would the contour length in this case be measured from the first carbon in the chain to the last?

[AWK]

In this case: from hydrogen to hydrogen.
Note, one hydrogen atom is wrong, as I said a terminal group depends on initiator of polymerization.
Hydrogen (H-...-H) is never used for this purpose.
Of course, for 552 units, an error will be much less than 1 %

[madscientist]

Thankyou very much for all your help AWK (and others), much appreciated.