Drop spindles w/original ball joints - cotter key hole?

[ctsandb]

I am putting a set of Early Classics 2.5" drop spindles on my 71 c10. I got the spindles off craigslist and I'm reusing my ball joints. When I went to put them on, I noticed that the mounts of the spindles are about 1/2" thinner than the originals. This results in the ball joint nuts being well below the cotter key holes. What do I do? Do I drill new holes? Do I put 1/2" of washer under the nuts? Neither sound totally great but I'll trust you're advice!

Thanks!