Thanks for the IDs Dr Seow!

As for the Potanthus species, lighting conditions and post processing differences can really affect the colour of these yellowish-orange butterflies. One quick adjustment could make the skipper more yellow or more orange. To further the confusion, different screens and monitors display colours differently. The use of the "redness" as a characteristic for identifying P. ganda has to be supplementary only... Checking whether the upperside veins are dark dusted or not seems to me a more concrete ID key.

I noticed that photographs of P. omaha showing strong dark dusting on the underside veins are often of more worn individuals. Perhaps the wear and tear also adds to the darkened veins. The Potanthus no. 2 (post 26) was very fresh and his could explain the lighter veins.

Just out of curiosity, when dealing with Potanthus, would you say that the upperside features are more conclusive in determining the species?