i think on cathaypacific.com, the wing location is indicated by the "triangles" and the light shading over the row numbers...so it seems like on this 346 config...rows 19-21 in J are over the wing...

but it didn't show the compartments...then i used united.com to check these same CX flights, from their seat maps it seems like rows 11-18 are in one compartment, and rows 19-21 are in the second...

so i guess if you want the first compartment, and not anything over the wing, rows 11-18 should be fine...