Forget about block placement for now
Read the tell tales. If the outside top of the Genoa is stalled but the bottom is not, move the car back in order to flatten the bottom of the sail and fill in the top and vice-a-versa. Once they both flow and break together, control flow with sheet tension so that both the top and bottom backside tales flows steadily and the inside tales just start to flow. Same deal on the main sail - read the tell tales. If both top and bottom are stalled, ease the traveler out. If the top is stalled but the bottom is not, ease the main sheet to get more twist. You will need more twist on a reach opposed to sailing upwind.Once you know that your tell tales are flowing well, then get a general reference regarding placement of the boom, blocks, etc but only use these positions as a general reference. Always sail by the tales.