A couple things here:
Cams in F series are not set with shims. There is a plate (retainer) that goes on the front of the cam under the timing gear that bolts to the front of the block front plate, that keeps the cam from thrusting forward. The timing gear is pressed on the end of the cam and keeps the cam from thrusting rearward. How far you press the gear on determines the thrust clearance, which you measure with a feeler gauge. Then a circlip goes on the end of the cam just for belts-and-suspenders. In other words, it is just about impossible for the cam distributor gear to be in the wrong spot forward or backward.
Ricardo - you have to take a long screwdriver and turn the oil pump so the slot is in exactly the right spot before you stab the distributor. This needs to be CCW from where you want the rotor to end up because of the (by now familiar to you) twisting motion of the distributor shaft as it engages with the teeth on the cam.
Note the proper TDC orientation of the rotor in this image:
You want it to be pointing at that bolt on the side cover when it is stabbed properly. You can be a tooth either way but this orientation will give optimal clearance to the distributor body and diaphragm for setting the static timing.