I would not go with the K factor transformers, I would install Zig-zag's.
Zig zags put out alot less heat, than the K factors, and this helps with the cooling system.
Harmonics are cancelled in the zig zag, harmonics are just compensated for in K factors, due to the "beefyness" of the transformer...
I would recommend talking to Jeff Lewis at Eaton, he is an application engineer, whom I have dealt with regarding this issue, the man taught me alot....
I just got done a job, that required tearing out alot of transformers and installing these zig zags, and now I am a believer in them...
Dnk...
