440 Jensen Interceptor Exhaust Crossover / Balance Pipe

Hi, we have a 1970 Jensen Interceptor in our shop that needs some repairs and mods. These cars run a 440RB motor and 727 Trans package. The vehicle is currently running an aftermarket style twin 2.5” exhaust system off stock manifolds with mufflers and resonators and no crossover pipe. The exhaust note is currently too rowdy for the client, he’s looking for a more refined, quieter note that better suits a “Grand Tourer” type vehicle.
We’re thinking that we’ll change the resonators plus add a balance pipe and would like to know if anyone can suggest an optimum location back from the manifold outlets for the balance pipe? Of course this will also be dictated by undercar space etc.
Any help would be much appreciated! Have added a couple of pics of some other Jensens FYI.

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