You have to realise that slugs travel through the soil. If you make a timber raised bed and run tape round the boards, it won't work. It's worked alright for me in other situations though. Table in greenhouse with tape round the legs etc. It depends what you mean by choice plants. Some are tougher than others. Apart from mass methodical extermination the only thing that I've seen work is slug pellets. And I won't use them. So I'm praying for a drier summer.