I can't say I'm all that familiar with that motor myself but since it's a Porsche engine the 911 engine rebuilding forum might be a good place to ask:
https://forums.pelicanparts.com/911-engine-rebuilding-forum/
My personal experience with that "T" is it's commonly used on german and domestic engines to run oil lines when adding a turbo setup but I don't see a reason why it couldn't be adapted for an oil pressure gauge.