Your preamp might be a bigger factor than the pairing with the Omens. J2 has a much higher input impedance than F7, so if you are using a tube pre with high output impedance, J2 might be a better bet.
Edit, I see you are using AR LS3... their website says recommended load 60k ohms, so I'd lean toward J2.
Edit, I see you are using AR LS3... their website says recommended load 60k ohms, so I'd lean toward J2.