There was an article in MR a while back that described how a guy attached a fishing line to the bottom of his poles, drilled a hole through the layout, strung the line thru then crimped a lead fishing weight to the end of the line. So if the pole was hit it just flipped to the side then automatically righted itself.
Another consideration about what composition poles will depend on whether the layout is for show and train running, or used for operations with switching, card cards, etc. The operations layout has more chances for poles getting hit by an elbow or hand.