it makes sense to get a long skinny shaft since I have this mounting
   thing, but since i'm doing this right now, i'm thinking of other
   solutions.
   I could glue or otherwise affix a dowel to something flat, possibly.
   I could buy a dowel from a hardware store.
   I could use a pencil.
   I could use a metal rod: this seems it would work better. Like, a
   coathanger may work.
   I could possibly use the bolts to affix a bent coathanger to the
   bracket, and lash the shaft to the bolts to keep it in place. Winding a
   cable might tighten the lashing.
   This seems unlikely to work given how my hands spasm and shake, but
   it's an idea and may work.