I 'm not an expert in the new training style but there are 2-3 very interesting threads in Tutorials and Guides section.
My personal opinion is that GK is a unique part of the game and it's not worthy to invest many greens to powertrain a GK and keep him for some seasons.
(specially after this http://forum.topeleven.com/%CE%93%CE...k-mystery.html )
I also don't suggest to invest to a ST (only for adding a AM position or maybe a sa like F-K S.specialist).