Just wondered if anyone could explain the difference between the above?  The high temp system seems simpler and cheaper.

The tube is 1.5m x 0.3m, unfortunately just a bit too big for a small kit per side.  I have worked out that to finish the plug (sonotube), the parts come to £227.64, this includes a laminate skin, pattern coat, polish etc.  Add the £314.40 for the large kit and that is £542.04.  I could save a bit of money by using 3 small kits, but for all I would save I might as well get the large.