need advice on my first grow outside

first of all i need the right seeds for the south of spain, which ones do you think on this list? ive grown skunk special indoors before which wasnt a bad yield or smoke imo, but was after something with bigger buds. is purple power plant worth it as its for outdoors and is fast/maximum yielding?

http://www.cannabis-seeds.co.uk/seed...ale-seeds.html

now what is this LST and tying. is tying where you can make the plant grow wider by having string pulling downwards on the branches to make it grow more horizontally. should i top the plant aswell if i tie it?