Guys,
The back plates used for the magnets are of course spinner plates. The system comes with magnets. 2 for each engine. I choose to use my own magnets as they are chrome plated.
I tried 4 magnets on each engine and got no better results. So I will be using only the 2 for each engine. The instructions state to crank the Master first and then the Slave engine. You can however start the Slave first. This way is easier. If the Master is running first the Slave servo goes to full throttle and will slowly back down, all the while flooding the engine.
When the Slave is running first the Master will not go to full throttle but the Slave's rpm's will come down the match the electric starter's rpm's, thus much easier to start!
Use the weaker engine for the Master, & stronger engine for the Slave.
I used a small strip of PC board for the sensors and mounted them to a strip of aluminum (brackets) running out from the 2 engine mounting bolts on one side of the engine. I then sloted the aluminum brackets for adjustments.
If you guys need any further assistance I'll be glad to help. Mark @ EMS/Jomar is very helpfull too.

Perry