Need advice on Twists

[ChemE]

I have a pretty well geared 3rd life, human, PM that already has a completed Magistar destiny on the books. I just leveled back to 20 last night and I need some guidance on which feats to twist in. I went pretty generic the first time. Maximizing spell pen, intel and such. I have one twist unlocked at the present but haven't used it.

[trog_star]

i'm aiming to twist in spell penetration from draconic and echoes of the magister from fateslinger.
mind you i have 3 FvS lives between now and then :P