Hand-matching resistors: high-end DMM vs Wheatstone bridge
The whole point is to match 2 different resistor values to each other, correct?

In that case, get 2 high quality fairly closely matched resistors R1, R3.

Then irregardless of the actual values of R2 and Rx, as long as they are closely matched the voltage divider circuits R1/R2 and R3/Rx will produce a near-zero voltage Vg. The smaller the voltage, the closer the match (assuming very good R1/R3 matching). You can now use R2/Rx in your circuits and they will be pretty well matched to each other.

There is another issue with resistor matching, though: temperature coefficients. These are often specified as max values and there's no telling if two given resistors will drift at the same rate or even in the same direction.