Firstly, beautiful car!!! I think regardless of "where" you post it for sale, the key for any seller is "how much will you take for it?" People tend to struggle with this more than how to post it for sale. The other factor is "how fast or bad" do you want to sell it. I have seen Panteras for sale by the same person for years at the same price. Clearly they have no burning desire to sell it.
Caution on BaT - the audience can be very brutal. Right now, it was looking like very stock original cars were doing well, but then a really nice custom comes up and makes big money. Just set your reserve on BaT and if no sale, oh well - it only cost you your time. I would think most people on this forum already own a P and the pool of buyers here smaller than Hemmnings, BaT, eBAY, etc. A good friend just sold her 55 Chevy custom on eBAY. I joked when she put it there and said you will never sell it - Damm if she didn't for basically her asking price of north of $150k. So I would consider it now. FaceBook groups is really a shit show. Bunch of people that have no business owning a computer, let alone a Pantera. I would be very careful of that.
Best of luck which ever way you go as some day we will all be in this position either because of a change of life, interests, or something else.
Lee