In reply to Kid Spatula:
Your 50m rope will be too short for lowering off many of the routes (at Guadelest,for example, many routes need a 70m). Don't forget a knot in the other end of the rope to be on the safe side.
It sounds like each of your ropes are "single ropes" i.e. fine to use individually on their own. I have climbed many times in the Costa Blanca and have never used anything longer than 60 metres for single pitch sport routes and have had no problems; there are some where a longer rope is needed but the guide will mention this. If doing a multi pitch route, such as some at Guadalest, (or a route longer than 30 metres) then you could use both ropes and then abseil, meaning you could cover 50 metres or so in an ab'. You do not need to clip both ropes through each draw.