But if the effect is turned back on the caster, doesn't it generate the resonating thing (because the caster also has a Spell Turning)? Do you see my confusion? Can someone help, please?
1. Like SR, the caster can ignore the Spell turning in the case of casting spells on him/her self. But that would not be the case from any other source (meaning all other friendly magic would be turned - be it from fellow party members or NPC's).
2. Use the resonating field chart.
Either is good, it's all in how the DM want's to play it. Personally I would use the second option, I like the planning aspect of it. The caster would only make that mistake once.
For practical reasons, if I were DM, I'd say the spell would work fine.
However, from a mechanical standpoint, the spell would be bounced back to yourself. This does *cost* 3 levels of spell turning, if you are using the spell.