Why would your back get worked less if you had the biceps being worked more? This is like saying a closegrip bench press won't be as good for your triceps as single-arm dumbbell extensions because the shoulders, lats, and chest assist them in the movement.
The best way to do a row is parallel to the floor, with your elbows coming up along your sides, utilizing an underhand grip. I should say, it's the best if you want maximal lat involvement, as well as giving the biceps the best line of pull. This allows more weight to be used. More weight to be used means more tension on muscle tissue. More tension will lead to more growth.
An overhand grip pulled to the chest (fairly high) will recruit the mid-back more than anything. Biceps get the most poor line of pull.
A neutral grip pulled midway will recruit the mid-back, but to a lesser extent than an overhand grip, as well as the lats, but to a lesser extent than an underhand grip. Biceps get a moderate line of pull.
An underhand grip recruits the lats primarily, also giving the biceps the best line of pull. The midback is worked much less (though still utilized) and the most weight can typically be used this way.
Your call. At the end of the day, it won't make much of a different. Do what is comfortable.