JD070780 Doolin

Hi, I am looking for some advice. My husband and I are currently employed and pay our tax through PAYE. We have recently started making money on the side from home through carpentry and profits will start to go over the £1000 trading allowance meaning we will have to register for self assessment and become employed AND self employed. Is this correct? If so, I have a few follow up questions below if someone could answer please.... 1. My husband earns £63,000 and I earn £12,000. My husband would be doing all of the bulk of the business work and I would be helping out with the admin, advertising and business correspondences. Does it matter who registers with HMRC as the sole trader/self employed based on this? 2. As my husband earns £63,000, would any profit we make be taxed at 40% as he earns that much? 3. Earning under the personal allowance myself, would it be best for me only to register for self assessment and have the business considered "in my name" as I would have to pay less tax on the profits we might make? 4. Would HMRC add the profits from our small business to remaining personal allowance I am allowed (£501), and then I would be taxed 20% on the remainder of the profits? 5. Do we both have to register as self employed? It isn't a partnership we are looking at (just a sole trader role). 6. Once registered and the first tax return form as been filed, is there any change to my employment payslip? Such as tax codes or the amount I would have to pay under my employed status. Would I need to let my employer know anything? Thanks for any advice/answers.