I used the orange fiberglass driveway markers. I did drill a hole in the right and left sides of the top tubing near front of the basket and ran a screw in the side to lock them in place. I had been thinking of some sort of clamp but this was just so simple without the added worry of needing something to prevent the marker from dropping out the bottom.
I've built a few of my own fly rods so I went to
www.mudhole.com and got
2 sets of ferrules that I epoxied onto the top of my markers. The ones attached to the basket were cut to length so they appear just above the hood as I'm driving. I attached the mating ferrule to another marker pole cut to length so that when attached to the marker in the basket I have a set of feelers just about the height of my camper so when driving wooded back "roads" I can see if that low hanging branch is too low.