Both will be great high wind boards for you. The E66 will have the same kind of general feel as your EVO 74, with very very good riding qualities in slower wave. But both due to the smaller size and due to the development of the EVO concept the last few years it will offer much, much better high wind and big wave capabilities. But it stil has the "vertical" and turny character.
The Kode 68 is another concept with a faster rocker. If will have more fin drive and prefer a more driven turning style and somewhat longer arcs.
In pure high wind control, both are excellent butt a bit different. The K68 can be loaded up over the fin and keeps a steady line, The E66 instead has a softer ride and dampen chop very well. A matter of taste and style which is best for you.
For onshore, if you're gonna ride waves, I would say the EVO is probably the best choice. But if you're more concerned about jumps, speed, backside riding and such things, the Kode 68 might be it.