There’s no change in the configuration of the seating for rail seats, still one-for-one but you just allow more people to stand in spaces so it would mean a change in capacity because you can fit two people in a space for one seat, although most go for one extra person in a space for two seats, just to be safer.
So seats in NSL1, Block 136, Row P, Seats 101+102 you allow three people to stand in those two spaces. You don’t need to change anything, there’s more than enough space for three people to stand in a space for two seats. The rules even state if you can accommodate them safely in the concourse you can allow two people to stand in every one seat space if you want, but most just do 2>3 just to be a bit safer (apart from at the ends of rows, so what you end up getting - like my examples from the initial post - is something like a 1>1.7 ratio across the stand).