Ron advised to focus on the primary.
After some research i ended by by flyback type transformers who function a bit different then normal transformers.
http://www.ionizationx.com/index.php/topic,2890.msg26982/topicseen.html#msg26982The term "Flyback Transformer" is a little misleading and its more useful to consider it as coupled inductors rather than a transformer because the action is quite different with a conventional transformer energy is going into the primary and out of the secondary at the same time it does not store energy. With a "Flyback" transformer energy is first stored then released.
So, the approuch for the vic system of Ron, must be using gaps between the cores..
Ron, i just orderd some of your recommanded cores and will use them like flyback,s..
See what comes out of it ☺☺