If you have an IB long haul J ticket, you will already have access to the arrival lounge at MAD. Just keep in mind that it's not the same as the departure lounges so it will take longer to get from there to your departure gate. (Haven't used it myself yet - so I don't know if it's airside or landside.)
Leaving from BCN I'd say it's not worth it. BCN is an airport where you can arrive about 1 hour before your flight without problem. And if you want to arrive earlier, there are plenty of bars and restaurants to keep you happy for a while.