Sorry, I don't have experience with the W-4 calculator so don't know how the "allowances" affect the withholding. I think what I'd probably do if I were in your situation is first get a handle on what my total federal and state tax liability would be (including the property tax break). Then check with my payroll department what the withholding would be with my given marital status and allowances, then adjust the allowances to match my projected federal and state taxes. I expect Turbo Tax estimator to have the 2018 updated tax calculations but I haven't found it to be as user friendly as when actually doing the taxes, it's more of a worksheet, you need to know what data to put in.
