Please reply to the list, not to me directly.
Axel has gave you the best possible replies.
Answer to your first Q has already been given; answers to your second Q are 1) I came up with the chi values empirically - meaning trial and error, 2) Current fix qeq/variant can not reproduce Rick’s model for at least two reasons: a) there is no intramolecular nor intermolecular charge transfer but inter-atomic charge transfer and b) there is no combining two different charge models (slater vs. 1/r) in one fix qeq/variant. So you will have to code it up.
Ray