Controlled draft induction is operator friendly but requires more hardware to work properly, p/s dampers that by nature are not linear to airflow [ most of the control is within 30% of the 90 degree travel]. Also if the draft inducer only runs at one speed, and 1 damper happens to be closed, the airflow through the open damper becomes greater than if both were open. For draft induction to be controllable the mass air flow/draft inducer needs to be able to modulate, maintaining a constant neg pressure in the firebox throught the burn. By doing this you can still have a small load of wood burning, modulate mass airflow down to a regulated differential pressure, thus allowing the damper air volume proportions to become more linear and controllable for a pid. The end result is the ability to have a low fire and still maintain combustion effiency. Again for this to work you will need a vfd to control a 3 phase motor, or a fan damper on the outlet side of the id fan, these are both do-able but require a lot of planning to properly inplement. With a smaller output boiler such as the froling, smaller draft id motors using pwm control make the technology more convenient for use.
The forced draft side requires 2 modulating draft motors, one for the primary and one for the secondary air control, this system is more easily controlled [linear] as the motor only supplys what is required as opposed to controlling with dampers.
As we are burning wood, o2 feedback is needed for either of there techniques to work accurately.