I've never been to Cuba to fish, but I worked at a local flyshop years ago...
From what I've heard, I think whatever line you use here won't really be "great" for Cuba, although if you really wanted to, you could probably make it work. The biggest difference is the warm water temperature down there...it turns our lines, which are designed for cold water fishing, into super soft and limp noodles. This is why some companies offer a range of warm water lines (like the Bonefish taper from SA, I think), that work well for fishing the tropics.
I've also heard that a good clear intermediate line is one of the most utilized lines for fishing the flats. You'll be throwing some heavily weighted dumbell eyed flies, as well as some large wind resistant flies...so don't try and look for lines that are presentation oriented. Distance with a good belly is what you'll be wanting in a taper.
Having said all that...and having told you that I have never been there myself (yet)...take what I've said with a grain of salt.

You best information will probably come from visiting your local flyshop where some of the trout bums may have gone there to fish themselves. I know that the guys at Sea Run go every year to fish for tarpon and bones in Florida...so they would have some great firsthand information for you. Good luck, and have fun!
Oh yeah...you'll most likely feel "undergunned" with your 8wt for most of your fishing down there.
