Couple more thoughts /answers for you. Older steel Jframes like your 60 ( and 36's, 49's, etc) weigh in at 19-20 oz. The newJ magnum framed 60's/640/649 are about 23. The alloy frame guns (new/old) are about 15 oz and the new scandums 12. A few ounces does effect how the gun shoots and (IMHO) to a lesser extent, carries (if holstered.). As "don't shoot" said, the heavier steel guns will be MUCH frendlier for recoil when getting to know /practicing with the gun. (Important to me since I like to practice with my carry guns regularly.) I also preffer the durability and finish of the all steel vs alloy guns. Grip area no brainer as they can be replacd for $10if you shop ebay.
Since you asked, I'd personally opt for the used 60 myself. I'm not a big airweight fan. They are commonly reported to have grittier triggers out of the box than steel models. ( The few I tried reciently lived up to the rep too.) I'm also not a big fan of DAo j frames (but do own a 640) . Call me a practical traditionalist I guess
In fact, I have and carry 36's,49s, 60's (new and old) and a 640. All are steel comfortable to shoot and carry well in a IWB type holster.
p.s. Just so your on the same page, don't forget to figure tax on the 60 and the $25-$40 FFL fee ( and possable tax) on the 642 for a true comparison.
Enjoy whatever you get &
Keep us posted!