Wheatstone bridge with capacitors needs to be balanced
If R2 is K times R1 then C1 has to be K times C2. It's as simple as that unless I'm missing something obvious. It's that by inspection.

At any frequency the impedance ratio of R1 to XC1 must be equal to R2 to XC2.

\$\dfrac{R_1}{\frac{1}{sC_1}}\$ = \$\dfrac{R_2}{\frac{1}{sC_2}}\$

Therefore R1C1 = R2C2