Maybe I'm a bit dense (OK paranoid

) but I want to make sure that I understand the details of substituting Parlon for PVC. I am wanting to order only one chlorine doner if possible to reduce costs. Since Parlon is a 68% donor compared to PVC as a 57% donor I would use a ratio of 57/68 Parlon as the substitute for PVC. Is this correct?
I saw one post that indicated increasing the % of fuel (red gum) to compensate for the lower % of fuel provided by using a smaller amount of Parlon compared to PVC.
As an example if the formula calls for 10 parts of PVC I would use (57/68)x10 = 8.4 parts Parlon. I would then increase the fuel (i.e. red gum) by 1.6 parts to make up for the missing fuel from the PVC. Is this correct?
Any other considerations to take into account in substituting chlorine donors?
Thanks for the help