One thing we've learned is that you can share beer buckets with your buddy. Hubby drinks Coors Lite only. I mix it up between Blue Moon or Miller Lite. So what I'm saying is that you can mix and match your buckets. You can even do it with a mix of domestics and imported.
Another thing we learned (and not sure if this is because we find a regular bartender who we stay loyal to), but you do not need to get your bucket all at once. Once we've established a relationship with a bartender, we leave the tab open, and the bartender will tell us when we're on our free beer. If we leave the area, and know we're going to see him again later that day, he will still leave the bar tab open. Again, at this point, we've established a level of trust..
Alternatively, get a beer bucket with lots of ice; you can try to keep it shaded, but when the ice inevitably melts, the bartender will be happy to replenish your ice so your beer stays cold.
One more thing ... on embarkation day, find a bartender and ask him what the beer specials for delivery to your room are. We got 25% off a case of beer, which they delivered to our stateroom and stocked in our fridge. This was especially nice when we sailed out of Barcelona and couldn't find Coors or Miller Lite. We enjoy keeping beer in the room to drink on the verandah, or to take a "walking beer" on our way to dinner. We find that beverage service can be slow in the MDR, and that tides us over plus gives the servers a chance to take care of other tables first. I would like to specify that is one beer we bring in a beer glass from the cabin. And really, since I did purchase the beer from them, I don't really feel guilty about it either. The next rounds we order from our assistant server, and he is properly appreciated.