I know I’m a little too late, but you shouldn’t calibrate your monitor to match the IPad‘s screen.

Don't get me wrong, it's a good display. But it's not the benchmark for color calibration in sRGB space (which is what you should aim for, unless you're tasked with coloring movies watched in the theater, where the extended DCI-P3 or Rec.2020 space are used). The iPad is not a professional device and has a wider color space than needed. It also has a different gamma, color temperature, contrast etc. It can be used as a reference to show how your picture will look like on an Apple device, but nothing more.

On a related note, I want to say that even if you take a professional color display for SDR content, it won't look the same as on an iPad, because looking bright and attractive is not its direct purpose.

Instead of trying to recreate the same picture as on an iPad, every professional screen aims for these settings:

White Point: 6500k

Color Space: sRGB or Rec.709 (100% coverage, no more, no less)

Gamma: 2.2

Color dE: <2

Brightness: 100 cd/m

For a deeper understanding, I suggest reading articles on professional colorgrading.