Not a fan of sandwich adapters. Your sending unit is a bit large to fit under the alternator (ie. directly into the OEM oil switch galley plug). You will need to use an isolation kit with uses a flexible line to remote mount the larger sending unit somewhere else in the engine bay. I suggest keeping an oil psi meter at the front galley plug.
The existing galley adapter has 1/8bsp threads. If the sender or the isolator kit uses a 1/8npt thread you "should" get a galley adapter that has matching threads or at very least a bsp->npt adapter. Some will jamb whatever 1/8 thread in there and hope it seals with tape or sealer without leaking. Meh