First off, I've never even seen one of those engines so take this with a grain of salt. Having said that, I've never seen an engine run worth a crap at 5*. That's old, emissions stuff and there tends to be some real improvements in idle quality and throttle response with just a few more degrees. 10* is certainly worth a try.
"I don't have an opinion, I have a dyno." -David Vizard
Live in a way that those who know you but don't know God will come to know God because they know you.