Leave the time sig at 4/4. Each bar will have two bars of your 6/8 song.
To query the library, you can, in the stylepicker

Filter the feel to Swing8
Filter to the tempo you want
Filter to the genre (likely pop)

Then try out styles.
If you want, you can do a text filter of 12/8 or 6/8, that searches the memo, but lots of styles have triplet feels and aren’t described as 12/8 in the memo

Have Fun!
Peter Gannon
PG Music Inc.