Setting LMC6001 offset voltage
You don't need the second opamp. These are typical circuits for offset control in opamps which don't have offset null inputs, like the LMC6001:  



You'll want the lower circuit, because there you can use the fA input current feature of the opamp. The other one has a much lower input impedance.  

Without R3 and the potmeter this is just a non-inverting opamp where 

\$ \mathrm{ V_{OUT} = \dfrac{R1 + R2}{R1} V_{IN}}\$

Adding the potmeter:

\$ \mathrm{ V_{OUT} = \left(\dfrac{R1 + R2}{R1} + \dfrac{R2}{R3} \right) V_{IN} - \dfrac{R2}{R3} V_{OFFSET}  }\$