Harry K wrote:
Can't agree on the 'faster'. True the flashing goes on fast but then
you have to cut at an angle every shingle that reaches the valley and
it has to be exact or will look crappy. Woven is a straight cut,
doesn't need to be exact and, in many cases, no cut at all is needed on
the last shingle per row.

On our crew we let the shingles at the valley run long. Then you snap
a line and cut it all in one pass to look right. The foreman gets to
do that job since he is worried about how it will look. Some times he
just uses a hook blade utility knife sometimes a pair of snips.
anyhow, so long as you stay on the line it will look good just don't
score the flashing.