gef..
i will correct u on ur answer...
u can have as meny peices as u want on a weight concept ticket as long as u do not exceed ur weight.
in most cases the IATA standard is as follows
economy (Y) = 20kgs
business (C) = 30kgs
first (F) = 40kgs
some airlines might give a few kgs extra as a good will gesture but they can charge u from 20kgs if u r over weight..
the excess charge rate varys from destination to destination but is normally 1% of the full economy fare.
so to benidorm u would be looking at no more than approx �10.00 per kg but again some airlines (charters) will have a set rate for each destination...