Hey Kurt i'm gonna be doing a similar build on an A15 soon. Have you thought about using a harmonic balancer? I found
this article which explains the benefits of using one, and i know Chris has been using one for the last few years and his car has been very reliable, despite the 8,500 redline (or maybe more). In fact I think this will be his third season without touching the engine, save for tweaking and routine maintenance. Anyway just a thought.