Two stoves were built, one mini with food can and one big using 4L paint can and 4 inch tin vent pipe.
As shown in four types of woodgas stoves built and compared, it proves that the 4th design produced higher temperature and cleaner burning, this test now is focusing on this design only and see how to optimize it.
Sizes do not matter as long as everything is built in the right ratio. The following picture shows the smallest one I built:
This is the bigger one:
As far as burning is concerned, good balance between primary burning and secondary burning is needed.
Also important is the good balance between burning and gasification (pyrolysis). Too much pyrolysis means that too much gas is produced which then requires a lot of air supplied in order to achieve a clean combustion.