The /θ/ sound is spelled with <th>. The /ʤ/ sound is spelled with <j> or <ge>.
This is a contrast between a voiceless fricative and a voiced affricate, close together in the mouth. It is not a problem.
The mean density value is 1.5%. The list makes 24 semantic distinctions, a loading of 59%.
bath barge bathing barging Cath cadge dearth dirge earth urge earthing urging earthed urged forth forge fourth forge lath large mirth merge myth midge nothing nudging Perth purge saith sedge thane Jane thaw jaw thawed jawed thawing jawing thaws jaws theology geology theological geological theologically geologically therm germ therms germs thimbles gimbals thin gin thins gins thinned ginned thinning ginning thin jinn thins jinns think jink thinks jinks thug jug thugs jugs thump jump thumped jumped thumping jumping thumps jumps wraith rage