Not all plants have 3 identifiable phenos.
Only F1 hybrids of unrelated strains will really distinctly show that.
If you force-hermed an OG, you'd get a feminized OG Kush F2.
Yes, you could then backcross and backcross to your heart's content using fem pollen but this is NOT something I'd recommend as I believe that over time you would end up wiht a weaker set of genetics.
Your better bet by FAR would be to research the ORIGIN of the OGKush and try to find its nearest relative that is available in seed form, and use that as a source of male pollen for your first generation, take the resultant male offspring with the STRONGEST OGKush traits from each subsequent generation, and use them to backcross repeatedly to your original OGKush clone.
Eventually you will get a generation that is 99% pure. This is a pain in the fucking ASS since you can't gauge flower traits in a male.

Guess where the '99' in C99 came from? She's a Princess offspring stabilized over MANY backcrossed generations. I'm not sure exactly what the method was but it sho' took a while, lol.

Oh- and onequickmove, be nice- Megatron has got this mostly figured out, we're here to clarify the fine points to each other. If you aren't going to help that process, hush....