good question!
i´m new to this sport too and don´t know which blade to buy!
4.0 or 4.9 ???? always the same question.
i think i´ll get me a 4.0 in the beginning because i don´t want to spend so much money on o kite. (well it´s not chaep anyway )
Also you can fly the 4.0 in a much wider windrange and in stronger winds too than the 4.9, right?
so, thats my opinion!
greetz, Phyronixx