be aware mechanical gauges have a nasty habit of rupturing so use an electronic sensor and gauge if permanent installation is your goal
The 928 ran a banjo fitting on the WUR outlet, a suitable fitting for the inlet would be the same as on the fuel head to injector feed from memory
when I was logging pressures during development I ran a HEL Performance 10mm to 1/8npt double banjo sensor take off
I'm pretty sure I have a spare one in my collection, let me know if you can use it and I'll go hunting
although this might be better