Your bead between the brass body and the clevis should be all you need - shouldn't need that buffer and as whatfly said you're between a moving and non-moving part. Let your bead be your buffer and not the hackle.

I've been making spinners since the early 80's, and I like yours but the bit of hackle you're using could be skipped and I don't think it would hamper your spinner at all not having it.