I've got a 60 under my Yota now. When I swapped to the 6 cyl I kept breaking every Longfeild I put in there (this was pre 30 spline kit) so I swapped to full widths.
If I were in your position with a DD I would personally go with the 30 spline Long kit. Bobby Long is a great guy with a great product and he went out of his way to take care of me when I was having problems. If I was running stock axles I'd give those 30 splines a whoopin...