I have built uprights that you can tie bottles onto. They are 2 legs and a bar across. All covered with PVC pipe. I have a ball of string to tie the bottles with so they will hang down about 12" or so...
If the wind is blowing, we will have moving targets...I have even painted the bolltes I am bringing. that way they will stand out...
Bring all your bottles...Plastic, of course...
Steve