Gary;
To get the scientific answer to your question, you would need to get a 'Performance Package' from US Sailing. It will give you optimal sailing angles and the corresponding angles of heel at various wind conditions. At $200 this is a sizable investment suited to the serious racer.
As a general rule, 30 degrees is well beyond any efficiency. For my Ericson 34, the highest degree of heel (from the Performance Package) is 27 degrees. At that point of sail, it requires a LOT of bodies on the rail and careful driving to hold the boat down to that angle as the Lake Michigan winds build.
When I sail with my family, I usually reduce headsail and use the traveller to limit the heel to at most 20 degrees. At that level, the boat is faster, safer, and much more pleasant.
Regards;
Steve Valentor