You don't need to use all holes... I am an avid fatbiker so I can explain all this....in the beginning of fatbikes the only thing you could get had a massive offset, so that the cassette was exposed and could be used reliably. IE a full cassette with no chain rub. To achieve this offset the rim had to be drilled offset as well so that you could get even spoke tension (17mm for up to 4" tire 30mm for a 5"). Hence the 64 holes since 32 is the standard for a pedal wheel in the recreational MTB world. The front uses every other hole on both sides of the wheel to create a symmetrical dished wheel with even spoke tension............. Now we have 170-190 hubs instead of maxed at 135 so doing that isn't needed anymore