A few useful functions and offsets I found for 5.4.7 18019:
Unit hitbox radius is a float @ [[unitPtr + 0xe4] + 0xf0]
Not rebased:
0x789748: void __cdecl GetCastRangeBySpellId(void *unit1, int spellId, float *minRange, float *maxRange, void *unit2)
0x788815: void __cdecl GetCastRangeBySpellPtr(void *unit1, void *spellPtr, float *minRange, float *maxRange, void *unit2)
So calling:
GetCastRangeBySpellId(unitPtr, 6603, &minRange, &maxRange, unitPtr);
Puts the hitbox diameter (radius x 2) for unitPtr into maxRange (6603 is Auto Attack, melee range), since it's the maximum range allowed if the unit were attacking itself (hence: radius x 2)
I've been looking for this forever, apologies if anyone else already found & mentioned it.