It depends on how you have your W-4 filled out.
If you have your kids listed as dependents on Step 3 of the W-4, your employer is supposed to adjust your withholding to take into account the increased credit AND for the Advance payments. However, the IRS has not yet released the withholding tables/formulas or other guidance in that regard. And if/when your employer (or their payroll company) implements those changes is another factor that will change things.
In other words, as of right now it is difficult to impossible to give you a good answer for how to 'break even'. I think analyzing things in August may give you a better idea for how to do things.
