..but of course your other problem is that, if you're doing only carry on, on the SJU to EIS leg, you will most likely have to gate check the carry on bag. Just make sure there is NOTHING in there for those kind baggage handlers in SJU to steal. I recently had to gate check a perfectly legal carry on bag in SJU because the overheads were full. I had packed a small carry on that I knew would fit under the seat, with my camera, lens, and jewelry, inside the carry on bag, so I took that out to make sure there was nothing they would want.

But overall, I would be with Fletch on this one. It probably will be ok, but I HATE tight connections on vacation, as I stew about it for months before hand.. If it's one ticket, they would have to still get you there, but it also kind of depends on what your options are if you miss that connection.