Sounds like you should've bought 42cm (drops 42 c-c) Vibes. I also have fsa k-force compacts 42cm and they feel like 40's since the hoods are 40 c-c. They felt alitte too narrow when riding on the hoods. Then I bought a few sets of 44's (deda zero 100's and fsa omega compact) and discovered the extra width between the hoods (44cm & 43cm) started to feel uncomfortable on rides longer than an hour or so. I ordered 42 cm omegas today (the hoods on these are actually only 41cm c-c) hoping to find the sweet spot.

I'm considering switching out stems and bars for rides of different length. Maybe easing up on the stretch/reach for rides longer than 3 hours.....