I did a whole simulation and missed the swap from S335 to S355 in the discussion, confirm what powder you have, the water volume of a fired case and the barrel length and I can give you something to check out. Possible accuracy below the listed maximum on the website, maybe give the details of your current S365 load to see if the software gets a similar velocity?
But start with Somchem load data that IvW listed above and it looks good on the simulation.
The PMP bullet is 152gr and flatbase 28.9mm long.
The Oryx 156gr is flat base 28.7mm long; nothing is it.
The extra 4gr bullet weight does not alter the load very much at all even seated at the same depth.
The 75mm listed on the Somchem site is pretty deep but you will have to see what your rifle throat can handle. Maybe able to push it out a but further.
At 75mm you have 10.7mm in the neck of the case.