Koni, how big and how often do the cats you catch pull your drag out? I am use to river fishing catfish in which they have the current to use to their advantage and little 3 lb cats can give you a good fight, I image its a little different in big lakes. However if your drag does get used alot I wouldnt recommend splicing line together, as it creates a weak point on your line. So not only will you have 60 yards of new line missing off your reel you'll have put 60 yards of line in the lake to get snagged and kill what ever fish you just hooked.
I feel this technique is a great technique to use when targetting trout, walleye, panfish, and bass. Since fishing for most these, except walleye, you normally will never hit 60 yards of line fighting these fish. With walleye trolling with 60 yards plus, you dont always have to worry about it since they are not the greatest fighters in the fish world.