On a non-level-wind reel, which thumb guides the line?

I understand a thumb acts as a level wind on a conventional reel with no level wind.

Which thumb? Where do you put your hands on the rod?

thanks,

J

Non cranking hand on foregrip with that thumb guiding. 

FYI... since we're on the subject.

Another benefit of an acid/spiral wrapped rod is that for a non-levelwind reel, you can offset the first guide just a bit to make the line naturally come back across the spool toward your non-cranking thumb.  You only have to push the line with your free thumb and it takes 1/2 the effort to level the line back on the spool. 

Erik

thanks!