Help Installing String Retainer

[Saint]

I am trying to install 1-2 string retainers on the new bass I just built. I've built basses before, but this is the first time I've needed a string retainer.

My question is this: where on the headstock would you install a string retainer for the G-D strings and, possibly for the A-E strings?
I'm using a moses graphite J-bass neck. I currently have the tradtional, round retainers; however, I am open to buying different style retainers if there's a benefit.

Thanks.