The further away from the PAP you place the MB, just means that it takes longer for the ball to find it's preferred spin axis. This CAN smooth out backend reaction, BUT, can also enhance backend reaction. It depends on the bowlers style. Speed dominate, more often than not, a far MB from PAP will seem like it smooths the backend out because the breakpoint won't be as defined and angular. Rev dominate, a MB further away, can enhance the backend motion because the ball doesn't spin up as fast and roll out, and has enough left for the backend.
The other factor is coverstock materiel and cover prep, and how quickly the ball wants to naturally slow down, based on friction. A super strong cover can have more backend reaction with a longer MB to PAP placement because even though the ball is slowing down because of friction and lane adhesion, there is still some motion left for the backend because the ball has not found it's preferred spin axis yet.
As far as the pin distance, it depends on how far from the VAL it is. A pin close to the VAL will create a more defined shape, with forward roll. This can be perceived as "weak" because the ball has used all it's motion, early. But, this also can create the perception of a strong backend reaction for a bowler who doesn't have a lot of hand, and needs that strong reaction to get the ball to change direction properly. A pin further from the VAL will have more continuation, but can be perceived to have more reaction, or "stronger" downlane because it hasn't rolled out and saves some energy for a heavier handed player. A weaker handed player may find a further distance pin from VAL to be smoother, because it doesn't have that extra "kick" to get it to change direction.