Anthony,
It has probably been mentioned to you elsewhere that for your needle(leaf) reduction needs you are going to need to play with your fertilizing schedule, decandling schedule, needle thinning/plucking(reduction of total needles) and your new bud removal timing. Getting the timing right with all of these things will ultimately lead to a reduction in needle length as the tree will not be able to produce anything larger than what you have hindered it to do. As Adair mentioned in the US we do not fertilize year round as this gives the tree too much energy, we do complete candle removal at the end of spring/summer, we wait until the new buds have emerged and opened with needles before selecting only 2 and we control the trees overall energy by removing needles throughout the tree. Unfortunately what timing works for us will likely not work for you and vice versa.
Dario,
When "growing" black pine for trunk girth you focus on trunk shape and on having a horizontal root spread. Otherwise let all branches grow for approx. 2-3 years from seed. At which point you cut the apical leader down to lowest node. This promotes back budding and will give you your future sacrifice branches and permanant branches. Selecting which is a sacrifice and which is part of the future tree is the harder part. Sacrifces are let grow and future branches are treated with ramification techniques. EDIT*
i just read Brents article linked above which is excellent. It pretty much picks up at the 2-3 year point as I discussed.
Hope this helps