Building a steady rest for large hollow forms was a project in and of its self. I tried a bowl steady but quickly found it would not support the large hollowform I was experimenting with. I then modified to bowl steady to use hard wheels on the bottom. This did not work as they did not have enough give to be useful. I tried pneumatic wheels on the bottom after making some modifications. They worked better but I found a pneumatic wheel was also needed on the top of the hollowform. I purchased some thick walled hollow tubing , and had a neighbor that is a welder make up L shaped bars out of round stock. I drilled and taped the hollow tubing and came up with a solution with 3 pneumatic tires. This worked rather well. over time I discovered the nuts and bolts of the wheel hubs need to be tightened or the innertube bursts. Unfortanatly the use of a uncut log along with the time it took to develop the tools resulted in the hollowform getting major cracks and becoming firewood.