[gentoo-user] Compose key and UTF8

Hi,

 I am using the US layout for my keyboard in the altgr-intlk variant.
 UTF8 is activated.
 Furthermore I use CAPS LOCK as compose key. I tried compose key
 sequences from /usr/share/X11/locale/en_US.UTF-8/Compose and many
 do work.
 So I think the basic mechanism is ok.

 But some came out as unfilled squares -- I think a glyph is missing
 here in the font.

 What is the best monospaced font to be used with UTF8 and which
 supports as many glyphs as possible?

 Thank you very much in advance for any help!

 Best regards,
 mcc