Help Connecting Dual Subwoofers

I could use some guidance connecting multiple subwoofers.

I would like to connect two subwoofers in a music only second stereo system.  I thought it would be easy to search on A'gon, google or manuals to find a quick answer, but what I found is geared towards home theatre or subwoofers with LFE, neither relates to my situation.  I am interested in using my preamp's second set of line outs to connect my subwoofers, and the subwoofers only have line level left and right ins (no LFE) and I am not interested in using the subwoofer speaker connections.

My question is should I split the preamp left output with a y and run the left interconnects to both subwoofer's left RCA inputs and then split the preamp right output with a y and run the interconnects to the right RCA inputs on both of the subwoofers?

Alternatively, can I just run the preamp left line level out to the left subwoofers left RCA input in and leave the right RCA input empty and do the same running the preamp right line level out to the right subwoofer's right RCA in, leaving the left RCA empty?

Is either preferable if both are OK?
Thanks
George