Hi Dave
Thanks, played around with the channels last night, with the glass curved and the two vertical sides also running at an angle, I got down to basics and made sure the long channel (rear) slides smoothly, next was the top channel, that it does not bind and seats easily. Keep in mind, that channels can also "twist" so had an interesting puzzle going.
The third channel, front one, this was the original problem, as the front glass section is only about 6" long, it was not parallel to the rear one and slightly twisted. Some cutting, filing and it now really slides easily.
Will finish then spherical joints this evening and then the test... holding thumbs. The last channel, being between the front and top, the one the same angle as the windscreen, will be done once all is working.
On the spherical joints, I am also making "floating pins" into some vesconite as the curve means that these pins must be able to move about 1". I will take some pic's and would appreciate your comments.
Regards
Heinrich