I know this thread is a little old but I'd just like to add my two cents worth.
Boat sailmaking and aviation sailmaking are very different fields. Boat sailmakers do a fantastic job of yacht sails and covers, but when you need skins for aircraft please, go to a sailmaker experienced in aviation work. Only aviation sailmakers truly know what is required in terms of accuracy, and appreciate the responsibility that goes with the work.
Spectrum do great work and we at Wingtech also know our stuff. No pilot in Australia should ever have to take their work to people who may not fully understand it. It is aviation we're talking about and it needs to be taken seriously.