Danpropertyquestions

Hi, I have a rental property owned solely in my name. It is worth £750,000 and has a mortgage of £350,000. I am a higher rate tax payer and my wife is a standard rate payer. I would like to transfer 99% the rental income to her. I believe I can use a declaration of trust and Form 17 to do this. Couple of questions 1. Am I correct that I can use the declaration of trust and Form 17 for this? 2. When is it effective from? i.e. when we sign the Form 17 or the declaration of trust or both? 3. Is there any capital gains tax payable? 4. Is there any stamp duty land tax payable? 5. Is it possible to chance and or undo the declaration of trust at a later date? Thanks very much for your help Dan