Can't you just use a shorter skewer? If not, yea, try some brass washers or bolts as spacers. Let us know how it works for you. Also, just curious how high off the ground the bottom of your front panniers will sit, looks kind of low but maybe not? Just be careful taking corners and curbs. Also agree with above, I've got an OMM front rack that is very solid and I've used it on my front shock mountain bikes with zero issues.