I understand that this is the boat that you have, and you want to make it work, but frankly I'm just not seeing it. To make more room for a shower in the head of a Pearson
35, you are going to have to eat into a whole lot of the port-side settee. I really don't see any way around that. That's where the table is, so now you have almost no room for dining.
Honestly, if you want room for a shower, I think you would be time and money
ahead, and end up with something that works a whole lot better, to just sell the 35 and buy a boat that has a separate shower built into it. A Pearson 365
would seem to me to be exactly what you really want.
Good luck, whatever you do.