I've decide to go down a different path. N4LQ posted a Youtube video a while back, which I found in my search for spreaders. He used a cheap pen tube, and zap straps to hold the wires, brilliant idea, but I wanted something a little more robust, and free.
I remembered I had 100's of feet of PEX given to me years ago, in various sizes. I found a coil of white 1/4" and made up this sample. I had a bag of 7.5" UV rated ties. It's amazing how much lighter this is over the ceramic Johnson bars. I am updating my wire as well. It was #16 and I found I had 1000's of feet of new on the spool #14 heavy enameled from my wind turbine prototyping days. So my new feedline will consist of the #14 enameled wire with these 1/4 diameter tube spreaders and the black zap straps. The tube has very little room for any critters to get in. It's pretty tight. Wire spacing will be 3", which is identical to the Johnson spacers. The 7.5" zap straps are JUST long enough. Impedance will be about 540 ohms.
Here are a few pictures of the sample I made up.
Cheers
Paul
VE7KHz