look at the Micro Magic sites they'll have plenty of information re the setup - don't have a site at hand right now but google it and you'll find a few. MM class is quite active in the UK and they have a good website too. MM are 500mm long so you can use the same electronics.

Go light - use a standard size servo for the winch which you'll use with an arm for the sheeting system and use a micro servo for the rudder. Use the smallest rx you can find that will work with your Tx and the whole system should be powered in 6v - you can find battery packs of 4 AAA size in 800mah which should be plenty or use a 2s 7.4v 800mah or lower lipo battery coupled to a bec system to reduce the voltage to 6v.

Hope this will help

G