I would love to go but I'm takin the missus to Florida for 2 weeks on 19th Oct.
The Sigma 36 is a great sea-boat not a "slapper"
You should do it in a week even with 2 days bad weather. You need a 24 to 30hr weather window from The longships to The Tuskar and you can always run to Lundy Roads or Milford Haven if it gets too nasty.
If you can get the internet on your phone, when in range, I find met.ie very good and I use it a lot especially the 3 hr forecast.
http://www.met.ie/forecasts/3hour.asp
Full Sails & Happy Trails,
Gerry