I changed all my dials and fitted a delimitter at the same time as the dash was out.
It's not that difficult but you have to be very gentle when removing the pointers from there shafts. Hold the shaft firmly with tweezers.
Also, take some bench mark reading before you start the job.
When car is cold, start it up and on tickover, record neg vacuum, rpm and oil pressure.
Take it for a drive and get it to normal running temp and record water and oil temp. When you get home record fuel.
Fit the relative pointers back under the same conditions. You will have to fit the speedo pointer while driving by getting a friend to drive at a fixed speed or set it against RMP v Speed.
I have a guide in word format that I can email to you if need be.
It explains how to remove the dash and heater cable tips etc.