I'm not aware of any test results specific to 0201 capacitors. However, I think the paper you refer to offers sufficient guidance as to how they chose the cutout size they ended up with with for 0402 caps.
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The length of the cutout is always equal to the end-to-end distance of two surface mount pads...
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As for the width of the cutout, referring to figure 2 - this shows the behaviour for 0402 caps. I'd suggest you can correlate the width of an 0402 cap (and footprint) to the cutout width to give yourself a rule of thumb that you can apply to you 0201 caps.
The paper goes on to discuss placing
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The ground vias near the DC blocking capacitors...
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The closer the better. This will be determined by the particular board technology and vendor you use. Look to them for advice.
As for the centre-to-centre distance - in the same way that you want the traces closely coupled, keep the caps close. Look to your CEM for guidance on how accurately they can place the caps and onto what size pads they're prepared to place 0201 caps. Then consider again the PCB technology and the required pad-to-pad clearance.
Consider all these points and I think that'll get you to a suitable solution.
Regards,
Alex
