Use circle dingbats that are more likely to be all the same size.

Specifically, use U+25CB WHITE CIRCLE instead of U+26AA MEDIUM WHITE CIRCLE,
and U+25CF BLACK CIRCLE instead of U+26AB MEDIUM BLACK CIRCLE.  These
are more likely to be the same size as the other two circle dingbats we use,
U+25CD CIRCLE WITH VERTICAL FILL and U+29BF CIRCLED BULLET.
Custom dingbat font which ensures all the marks are the same size.
Beginnings of alternative sprite-based, less ambiguous symbology.