He will have a ceiling of 32,800 to be taxed @ 20%, so he should move 10,800 of his standard rate band to his second position. This will mean the first 10,800 will be taxed at 20% and the remainder at 41%.
If your husband has standard single tax credits, there will be no benefit in moving some to the new job as he will already be using them all. If he has the married rate tax credit, it would be beneficial to transfer €500 tax credits to the second position.