How to increase an analog Galvanometer sensitivity ?

[BrianHG]

The problem with choppers is noise - not the output noise but the noise that its input chopping action injects back into the circuit that you are monitoring.

Thanks to the series input resistance in the circuits, you can cap filter that with a 1-10nf.  I would also decrease the 1m in the last circuit, the one using the negative input, to 100k.

[Tj138waterboy]

Sorry to beat a dead horse but this topic has made me question the layout difference in voltage sense and current sense depending on application. I Have read through most of the Ucurrent and picoammeter posts and now my brain is mush. I will do my best to explain my goal which is what I would assume is needing a dual purpuse whetstone bridge null as well as voltage reference/hamon divider null.
My current setup is using an ad620a INA due to the 1 resistor gain gontrol. I know this isn't best specs for either purpose but will be easy enough to replace.
Where im having issues is that I purchased a defunct Fluke 931b rms differential voltmeter that I lost interest in restoring so am going to repurpose but want salvage what I can to make a new possibly improved board.
The center 0 panel meter measures 3.16k across terminals
With on screen print showing volts-% deviation. Im unable to find any free online schematics but assume that the rotary switch decks are similar to the 8xx series fluke.
If suppose I gut the whole meter leaving only the panel meter and only using to null whetstone bridge "externally", and comparing 10v references or hamon dividers, which circuit would suit both needsor would I need both. I already jumped the gun by tying 2 10v ref outputs to the + - of the opamp just to test the gain amd had bad connection which pegged the needle.  I would like to know if its better practice to have maybe 4.6k resistors in series with unbuffered vref outputs to limit current or is there some form of magic with the npn transistors in the schematic on previous page that would limit current to stop needle from hitting limits hard.  Will post schematic shortly. Also side note I have a cheap ebay 35 mV galvo that measures 100r across terminals that could be used as well.