There are no individual exemptions to adjust withholding anymore. I have no idea how they are going to do it going forward.
Since the Standard Deduction is much greater than itemizing and my kids are grown (no Child Tax Credit) I divided $24000 by $4050 and rounded it down to an Integer. This gave 5 Exemptions and I let payroll figure out the rest.
If I had the Child Tax Credits I would add the Credits to the Standard Deduction and divide by $4050 and Round that to an Integer.
It is possible to get withholding more accurate on the W-4 but it would take to long for this forum.