I've taken Tres' class & got insurance (T/S Cig) through Elton Porter, who Tres recommended. They gave me a 10% discount as well.
The guys I took the class with were buying a 36 Nortech & listened to them on the phone with either Elton Porter or Bob Luellen & they had no problem gettting ins either. Tres even made the call for them at the ramp after completion.
Insurance or not, I highly recommend Tres' class for anyone running a 70+ mph boat.