While I rarely make boards, a quick search for trace width in this forum turned up this one from Steelgoose and Old_Grey which implies while you can't change trackwidth globally you can change it via inspector on a by trace basis. That said you may be better off with one of the more advanced packages
(edit) I just tried a soic 18 package (don't know if that is the same spacing you are using) and ran a wire from a resistor to a pin then selected the trace and changed the track size in inspector to 8 mil and it goes between the pins fine (after I reduced the grid size to .01) not ideal but it seems to work as long as the 8mm trace is fine enough for what you need to do.
Peter