For anyone that is interested I thought I would share my pad hack for the Logitech Dual Action pad. The pad works on PS4 (legacy SFV), PS3 and PC. It is my first attempt at a pad hack and was very pleased with the result as everything worked properly.
Ok onto the hack. It is sadly not common ground but there are four shared ground lines.
Up, down, left, right
Triangle, circle, square, cross
Share, Option, L1, L2
It’s a fairly straightforward job to solder as there are some big points at the end of each signal trace so if your soldering skills are bad like mine you get 2 chances at it.
Hope this has helped anyone that has one of these pads laying around