1st gear shifting at 20 mph about 3.2-3.4 rpm
2nd shifting at 35 with 3.3 rpm
3rd shifting at 55 to 60 (depending on traffic) around 3.5 rpm
4th i shift around 70 at 2.3 rpm or 80 at 2.6 rpm
5th at 70 is 2.1 rpm and 80 2.4 rpm.
Sounds like high rpm:s. I have some experience with diesels and using the lowest possible rpm above idle is usually the most fuel effeicient even if the turbo doesn't charge much. I try to keep the rev:s between 1.1k and 1.4k for normal driving and slightly higher up to 2-2.4 for short bursts when accelerating fast. Slower speed - closer towards idle.
This usually means 1:st gear one or two carlengths unless creeping forward really slow. 2:nd from 15km/h. 3:rd from 29-, 4:th 40-, 5:th 51-. 6:th 70-km/h (42mph). This is also how my current automatic shifts with moderate to medium acceleration. It wants the rev:s to be 1.1-1.2k as much as possible.
I have an 03 Jetta TDI. The key to fuel economy in a diesel is knowing your power band and what RPM your engine puts out peak torque. On my car that is between 1900 and 2000 RPM. That puts my road speed at 55-60. I keep it at 55 and get 52 MPG on average. This applies to your shifting and cruising around town too. You don't rev a diesel to 2500 or 3000+ rpm unless you are trying to climb a hill. You will actually get up to speed faster if you shift at lower RPMS. I will normally not shift beyond 2250 RPM. Your torque begins to drop after 2000 RPM because you are outside the power band. I don't overfill tires or practice any kind of hyper mileing tactics. Fuel economy is all about RPMs, powerbands, and safe following distances in order to minimize wasteful braking.
Max torque on even small Diesels is about 1750 RPM so unless your in a hurry change up by 2000 RPM, drive ahead ease the throttle to arrive as traffic clears, every time you
touch the brakes you are turning fuel into wear and wast heat, but body panels are expensive so drive safely.