Here's a thought tho: you are running a supply line to the turbo of oil, and you are running a drain line from the turbo. If either of those come off, you'll lose pressure. edit: you won't lose pressure with the drain off until you're way low on oil lol. Just saying.
I'd rather KNOW I lost pressure, even if its just lucky that I happen to glance at the gauge. Luck favors the prepared, so I prepare.
I also use my pressure gauge to tell whether the car is warm and ready to be treated to some forced air.
I have the glowshift gauge and sender, no issues. Maybe in the spring we can look at trying your gauge on my sender to see what the problem is.