to op, we're actually on the same path. although i might be targeting ppd at the moment while i'm testing this out. I'm doing lots of research as well and I've yet to know which will work for me. But regarding about the spun articles for tier 1-- people here mostly suggest to use unique or original articles for tier 1, some even claim that you should treat your tier 1 like your money site. My thoughts on this is because if your tier 1's do no pass human moderation, they get deleted, and you link juice stops thus a massive drop in rankings.
But for me, I'm planning to semi-churn and burn, i will try to build web 2.0's as tier 1 with auto spun articles. then blast them with contextual backlinks using gsa, then spam tier 2 with about anything gsa can get.
Let us know about your progress. I'm following this journey. All the best, good luck!