To the OP,

Something to consider which puts everybody at a disadvantage on a first build.

While most or all spoke calculators use the same basic formula which is nothing more than simple(?) trigonometry, there are a number of fudge factors that they may handle differently.

The first and most significant turns on the ERD. These days, most Americans consider this to mean the diameter taken at the tops of the nipples, or intended spoke end circle, Europeans often consider ERD to mean the diameter at the nipple seat, which is about 5-6mm less. You measured the ERD yourself and so know what you mean, but you don't know what the programmer had in mind.

Other fudge factors include an allowance for the longer path of laced spokes vs. the straight line route, elongation of the spoke under tension, the difference between the inside of the elbow from where spokes are measured to the center of the hole where hubs are measured.

So, even with indetical data entered the various programs will give results varying by a few millimeters. This is why it doesn't matter what program you use, as long as you;re consistent. Once you build a wheel, you'll know how different the results are compared to what you expected, and can from now forward "correct" the answer if you use the same calculator, and enter consistent data. However, the 1st build is always something of a crapshoot.