The MinionPro option swash makes \mathcal use Minion swash capitals. The position of math accents on swash capitals could use some adjustment (see below).
For a single accent, applying \skew{6} appears to work well. I suppose I could define a command, say:
\newcommand{\accentcal}[2]{\skew{6}{#1}{\mathcal{#2}}}
Is there a more flexible alternative? One of the MinionPro developers suggested "modifying the kerning files", but I am not sure how to do this.
\documentclass{article}
\usepackage[swash]{MinionPro}
\begin{document}
\[\begin{array}{ccc}
\hat{K} & \hat{\mathcal{K}} & \skew{6}\hat{\mathcal{K}} \\
\hat{C} & \hat{\mathcal{C}} & \skew{6}\hat{\mathcal{C}}
\end{array}\]
\[\begin{array}{ccc}
\widehat{K} & \widehat{\mathcal{K}} & \skew{6}\widehat{\mathcal{K}} \\
\widehat{C} & \widehat{\mathcal{C}} & \skew{6}\widehat{\mathcal{C}}
\end{array}\]
\end{document}
Best Answer
Please try the fixed scripts here to generate the corrected metrics automatically. My result from your code: