I will be surprised if there is a clear advantage either way. From a story point of view, I think we will have to give a slight edge to Tarquin just because he will need to hold his own until the rest of the LG can arrive to drive OotS down into the temple. After all, Elan can't defeat his father if he doesn't know it is his father... I hope for some neat trickery to keep Tarquin alive, which should be interesting to read. So... by an edge... I will give the advantage to Tarquin simply by keeping the Order engaged at the top of the ziggurat, which I would bet is his goal. Nothing real clear cut or overwhelming though.

As for the two evils... I would have to edge towards... eh. I dislike both. Abstain.