Sorry my bad I did not explain my setup.
I only need y splitters at preamp end because I am also sending a tape out signal to tape decks.
In your case I would just run one cable from each l&r pre out to each sub.
I would just go into one input on each sub and forget the y splitters altogether.
However if you have them you could try both methods although I honestly doubt you will hear any difference feeding both l&r inputs on the subs.
I only need y splitters at preamp end because I am also sending a tape out signal to tape decks.
In your case I would just run one cable from each l&r pre out to each sub.
I would just go into one input on each sub and forget the y splitters altogether.
However if you have them you could try both methods although I honestly doubt you will hear any difference feeding both l&r inputs on the subs.