Kirt,

Since Wouter needs time to look things up, may I help you out on this one?

Spi pole diameter(ouside)is 40 mm. Spi pole length as supplied by AHPC to me is 3.300 mm.
Strut length between bridle plate and spi pole may vary according to luff length of your spi. I made a prototype one that is a one piece units from 16 x 1 mm stainless steel tube. See attached picture. To make it clearer a detailed drawing is available too, showing the dimensions in mm.
There are 2 small lines from snuffer ring. One is supposed to go to the bridle attachement on the closest hull, the other should go forward in an approx 45 degrees angle to the spi pole eyelet riveted onto the spi pole forward of the snuffer ring. On Wouters picture you noticed the spi pole is blank, so he had to tie it to the closest item. This line should prevent the spi from getting stuck between the ring and pole.