Draw testing is done on just the bunches prior to the wrapper being place on the cigar - so no, they are not precut.
As to the actual value of using draw testers, this is one of those ceaseless arguments among cigar makers.
On the plus side, when calibrated and properly maintained they work well and can be quite useful.
On the negative side, they tend to be rather fickle and are seldom properly calibrated or maintained making their readings of little value. Also they tend to get small pieces of tobacco lodged in them that skews the readings.
However some cigar makers argue that even if the machines are not working well, just having the buncheros see that all their bunches are being tested has a positive impact on their overall work product.
Personally I am not anti-draw tester, however I do not subscribe to their use myself.
BR,
STS
