It's always very difficult to get a real picture of what is happening during testing, mainly because of the differing fuel loads, with an extra 10kg slowing cars on average by around 0.33 seconds per lap. But in the end, everyone did do short, sharp runs for their fastest times, so there was no real difference in run lengths to factor in, which makes it more accurate.
Most teams ended up doing here best times on the softest C5 compound, and around Barcelona that tyre is a one-lap special. Pirelli's compound offsets are usually a bit of wishful thinking and never really make sense to me as they are too big compared to what's actually shown on track.
I normally form my own opinion watching what the drivers actually achieve, so for this new Pirelli tyre range I've gone with the following: