A few tidbits:
Be careful using capillary tubes for oil pressure gauges. Have seen the tubes break and also seen gauges fail internally, both cause leaks that drained the sump over time.
I had a hydraulic shop make up the hose with fittings. It’s rated to 6800 psi. A bit of over kill but I didn’t want to use clamps or copper tubing with compression fittings plus that was the only hose we could find in 1/8”.
I didn’t know the gauge itself maybe a week link. I’ll keep an eye on it.
Also be careful putting a tee and nipple into block to connect both the sender and tap for mechanical gauge. That cantilevered mass and the vibes in the block can fatigue the brass nipples at the thread roots. Breaks off and oil goes spraying across engine room. Use steel fittings or hyd hose and mount the tee remotely.
That is my concern. I didn’t even think of using steel fittings and mounting the tee remotely. A great idea.
And you do need alarms. Many engines saved by these. You may say you look at gauges every 30sec, but I'm sure there are situations (bad weather, someone taking over the helm, etc) where the gauges do not get watched. A good alarm system is worth it.
We have audible gauges. That was one of the reasons I used the tee for these gauges. The other oil port is also tee’d with brass for an alarm sensor. An easy fix to change steel.