1st issue:
These are the two ports on my sabro split unit. The smaller one fits perfectly with the manifold gauge line. The bigger one doesn't. I measured the port sizes (Outer Dia) as well as the cap sizes (Inner Dia).
Small port OD 11mm (0.435")
Port cap ID 7.5mm (0.296") (difference may be a bit too much, maybe wrong reading or otherwise - this port fits gauge connectors)
Big port OD 16mm (0.63")
Port cap ID 15mm (0.588")
What size are these two ports and what kind of adapter do I need to connect the gauge with this bigger port?
calling @Xulfiqar @SER_GTR to the rescue!