I primarily work in Danish; but I use a US Intl AltGrDead[0] keymap, so I can access most needed symbols without the compose key, such as æ (altgr+z), ø (altgr+l) and å (altgr+w). But I still wanted to write ⅚ more easily, so I also added the compose key for even more symbols.

[0] The AltGrDead variant just means that the regular dead keys on the US Intl are flipped; e.g. ' is now no longer dead per default: I have to hit altgr+' to make it dead (i.e. an acute accent (´)).