I just replaced my 60G's with duraterms, I had thought I had a few bad one's,, turns out it was just one dead, the rest all would light up in about 12 seconds' to a hot and not get hotter warm red hot glow.
The Duraterms, lit up in about 10 seconds, to what looked like a little hotter red. This could be what seemed to be a 2 year old plug, and a brand new one.
I also think if you are going to use the 60G's it would be happier with a extended glow mod,
Either way, they both are sef regulating,, and you can put the juice to them longer than they really need, and not worry about overheating and burning them out like the old 11G and 9G's Hope this helps.