A carrot question

I've always grown my carrots in buckets - not having much space - and gorgeous they are too with not a carrot fly in sight.
Now I have a lotty - yay! - and we're in the process of claiming it back from several years of neglect. I'd like to grow more carrots next year and have heard that raised beds are good way of foxing the carrot fly.  I have space for a raised bed or two. Is there an optimum size - height? width?  I've read that carrot flies have peculiar flying habits but that we can outwit them!

I recommend that you stick with the buckets. I don't sow carrots anymore in the ground. What the carrot fly miss the slugs don't. Add another 6" between the potato rows and you will have space to line the buckets up and cover with net.