Timing is easy.
Just place the crank arm vertically. (straight up or straight down)
Then set set the eccentric so the high point is extended horizontally all the way forward or all the way back.
It is just a matter of having the eccentric 90 degrees to the crank shaft.
Regarding that screw on the side, it should be tight and it serves only to hold the outside disc in place which is just there to keep the eccentric straps from falling off.
Gil