I have a 7:1 main as well and that is not enough to sail the main out of the hand (at force 5).
If I can't would the problem be that the main isn't flat enough? Although I have the impression the main is fine.

When it blows I haven't started changing diamond tension and spreader rake. At our club the Infusions have a rule according to the wind and crew weight (spreader rake is changed according to crew weight, diamond tension is changed according to the wind force). The put a little measuring machine that says the kg of tension on the diamond).
Anyone with a alu wingmast that adjusts the diamond and can share some figures?

Gill