I can only speak for what Iberia's restrictions were, but I think they're pretty similar to what most of the other international carriers were saying. I personally had 2 free checked bags, but that's because I bought my ticket before the rules changed. I'm pretty sure most airlines, it's one free checked bag now (if that). The checked bags are limited to 23kg, which is approximately 50 lbs. There's a fee (on Iberia, it was 60 euro) for anything over 50 lbs. Your carryon, besides the normal size limitation, is supposed to be a max of 10kg, which is around 22 pounds. I like to make sure I have a good selection of clothing, underwear, etc, in my carryon in case my checked bag doesn't make it, so that 22 pounds was iffy. You're also allowed a "personal item" which could be a purse, a laptop bag, a briefcase, etc.
My suitcase came in at just under 50 lbs, so I was OK, and, as I said, American didn't weigh the carryon, so I was OK. Going from BCN to Israel, and then Israel back home, I wasn't so worried about what made it & what didn't, so I checked both my suitcase *and* my carryon, which meant it could then weight 50 lbs, which it easily managed. Anything important/breakable I put in my enormous "personal item". The gal in Barcelona weighed both checked items together, so I'm not sure how well I had the weight distributed. In Israel, they were both under 50 pounds.
Hope that helps. Let me know if there's any other details you needed.
Sayhello