It’s almost a sweet mint…like spearmint or something.
Try Flavour Art's Spearmint flavor (
FA Spearmint via BCF). It's a refreshing spearmint. Not harsh. It has a little sweetness. TFA, FLV and CAP also have spearmint flavors.
You might have to add a touch of a menthol flavor to further develop what you are looking for. CAP, FW and FLV each have a menthol flavor.
And, perhaps adding a wee bit of a sweetener.
I sincerely doubt that you will ever be able to recreate what you personally experienced with Newport cigs. Something close? Perhaps.