Keep this in mind with the weighting... the 60 has more weight on the rear, where it counts. If the tractors weighed the same, the 60 would easily do more as a higher percentage is on the back end.
My grandfather had a 50 A and a Super MTA, and when it really got snowy, the A went on the manure spreader, dispite no live PTO. Why? The front wheels on the MTA carried too much weight, and would plow into the drifts and the tractor would spin out. The A, especially with the tongue weight of the spreader, would ride over the hard packed drifts much better.
The A is still here, with fluid in the tires. The MTA went to the junk a long time ago.