The variation between gauges is only a few %, for cheap gauges thats to be expected.
You dont have 1 cylinder way lower than the others.
Best you just drive the car & enjoy it.
A new seal on the oil filler & a clamp on the breather may be a good idea so as to keep things clean.

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving