Coming into this thread a bit late, but...
The sail in my avatar was a 7.5 race sail I made myself in the early 90's. I made 4 or 5 sails back then. I figured there wasn't much point making sails that cost more than a bought one, so it was mostly an exercise in building sails on a budget. Had some highs and lows, but it was in all an experience that I don't regret. I learnt a lot about what makes a sail work - the good part about a home-made sail is that you feel quite comfortable in re-cutting it, so each of those 5 sails was tried with a variety of luff curves, re-inforcements, batten types etc. etc. Once you have made a few, you start to see where the broad seams are in production sails. Some wave sails have bugger all - it's all in the luff curve.
The highs were the feeling on blasting around on a sail that you had made, and I picked a trophy here and there. The lows were sails that blew apart while rigging, and at one regatta down in Meningie (you could ride a bike around the course now

) I turned up with my own sail, and was at the front of the fleet for the first morning in 20 k winds... and progressively moved to the back of the fleet as the wind lightened up over the weekend. The sail was tight as a drum and had no bottom end. It's easy to make a sail that is good in high winds or low winds, but not both. It also takes a bit of courage to turn up at a beach with a home-made sail - but everyone starts somewhere. About the time I was making sails, the Severne boy down the road was getting into sail making too - I've heard he is doing quite well

Anyway, this story is sounding like Grandpa Simpson. Did I mention I had an onion tied to my belt?