Did a search but couldn't find the answer, so I apologize if this has been asked and answered a zillion times. Here goes. I primarily need a non-steel double V wheel that can carry reasonable loads (within its spec'd limits) but doesn't develop flat spots after months of being stationary under said load. I don't need critical accuracy at any time, except for no flat spots - ever. Delrin or polycarbonate? Or something else (besides metal)? Speaking of poly double V wheels, while OpenBuilds doesn't seem to currently list them for sale, they do have a beautiful picture of one in their 'wheels' section of the parts store web site, so I'm assuming they're somehow available. I emailed OB a few days ago asking about their availability but haven't heard back. Thanks in advance for any help you can offer!