Don't wait to lace and get a nasty surprise. Before lacing, test a nipple and spoke and determine how much overrun that combination will allow.

As for spoke calculators, they're electronic "calculators" and any will give very consistent results for any combination of entered data. However, there are adjustment factors built into each one's formula, and different calculators will therefore give slightly different results. So the key to getting accurate predictable results is to stay with the caluclator you're used to, and enter data the same way, especially the rim diameter, (ie. at nipple seat, vs. adjusted for desired end of spoke). Once you know how far and in which direction a result needs to be fudged to give you the desired result, it'll be the same for every calculation using the same methods.