Hi Wayne
I guess you have to do some major re cutting. An 'A' mainsail foot is approx 1.8m long and the Stealth's is 2.3m ish. So as you probably already found out the boom is sticking out beyond the transomes! Maybe you should turn the main upside down and have the mother of all fat heads ;-0
Seriously, I hope you do find a fix and if you need some measurements of the luff curve I recorded my Landy's prior to a re cut. From memory the max curve was 105mm but I have the measurements taken at each batten pocket end.
I was going to mention that a sinking stern could be attributed to your midships but that would probably be to polite for this forum at the moment.