molleur, froggyman and Mister Towed - thank you very much for your help. Mister T thank you for the explanation, I understand the system a bit better now. Thanks for the links to order the parts too.
Mister T I hope your Speedster build is going well - did you started the build thread already? I've enjoyed your Sammio thread a lot, so I hope to read about building the Speedster too.