I assume your D60 is a semi-float?
If yes, then stick with 4.10 gears. If you put 4.30 or 4.56 gears in your semi-float, you have go with thin-cut gears, and that makes the pinion gear weak. I actually broke a pinion gear tooth in my 4.30 gearset, and that's what prompted upgrading to the larger carrier and thick-cut 4.56 gears (Mine came with the full-float, which was actually a D70 housing with the D60 gears inside.
I got the gears too hot towing the big tailer up to Alta, and this may have weakened them. About a month later I was loading snowmobiles into the trailer, which required a long run and jumping them into the trailer because of the ramp angle. I did not set the parking brake, and when I pulled away I instantly heard "thunk thunk thunk" off a broken gear in the diff. Still was able to drive the shop though!
Also, I would worry that gears lower than 4.10 could put too much torque through your axle shafts. In fact, I'd say just putting on 35" tires would probably pushing the limits of a semi-float axe.
So.... with all that said.... I plan on upgrading to F450/550 axles front and rear, pending parts availability and scheduling at QuadVan. That means there may be a full-float Dana 70 with Limited Slip coming up for sale soon