For me - and this is just me - I'd probably dial it somewhere between 25 and 40 and be happy as a clam. I've run 21, 25, 28, 30 and 40 using various accelerator cards in across the A2000 and A1200 and all of those speeds feel about the same to my eyes in most applications. I think 40 is the fastest I've ever pushed anything and I was happy with it.
Super exciting, @terriblefire!
Are you actually nearing a small-batch production run?