I 'built' the oscillator in spice with good results. I did discover to much feedback is easy to obtain. If you step L2 up in value it will not be long before you discover its limit. I took a short lead and made a single turn coil in the core I intend to use and it had .3uh so there will be a need to not be to zealous with the feed back winding. 2 or 3 turns should do.