Wire wheels on a Bugeye help

Listerati,
        A non-lister needs to know how best to fit rear wire wheel axles in his 
Bugeye. I pointed out to him that this may be the reason for leakage. I 
recall the ww axle is longer. Can he grind some (how much?) off the diff 
end of the axle? or is there more to do?
        Reply to all, as he is CC'd.

Thanks   Peter C