The handles are actually pretty simple. They are loc line segments
www.loc-line.com
I'm sure you've seen them many time for lights and strobes,as many manyfacturers use them to attach their products. Originally they are cooling systems and can be bought at these companies by the meter for a much cheaper price then from the scuba industry. I bent them to the position I wanted and filled them with marine exopy adhesives so that they stay in position. At the end I put a skrinking tube over it which you can get in electrical supply shops, this is the blue rubber hose you see on the pictures.
As the Gates has only manual controls in different locations I found the original handles always too far away from the controls, so I solved the problem this way.