So you are saying that 34* gives the best initial launch? Without measuring accurately, it seems like it would be hard to call... but then again, you do this stuff all the time!
Its not rocket science. At 28 degrees, it would not even squeek the tires anywhere. At 34, it would move about a foot, and then start hazing them.
I held it at 34, because I was not real comfortable going beyond, and I don't want the N/A tune up to be radically different than the Nitrous one.