I live in Portland, Oregon, USA. My garden has two Austrian Black pines (Pinus nigra). They were both planted 17 years ago, one was pretrained in the Japanese style, the other a balled and burlaped tree about 5 ft tall. We initially were going to let this tree grow naturally, but changed after the first year. First removed 1/2 of each candle at May pine pruning time. Later we changed to removing some select branches and all candles growing straight up. This has altered the growth habits of the tree, but it is still large for a Japanese Garden, but it sits at the lower margin of the garden space so serves as backdrop to the garden. The other tree is maintained more as a specimen tree.
The Austrian black pine is a very aggressive grower so we shorten the new candles about 3/4 and remove completely the lead candle, the upright grower and the downward grower to leave just two short horizontal candles on each branchlet. The needle do not become shorter and the long needles maybe detract form the Japanese Garden ideal. I also have two Red pines and 3 Japanese black pines and 3 Pinus contorta (shore pine) and 1 pinus parviflora (5 needle Japanese white pine all maintained in strict Japanese Garden style. The Austrian black pines shaggy look is a good contrast. I will take new photos of these two trees when the snow and ice melts that we have on this day.
From your photo, I think I would try to remove some of the upward growth in your cloud branches to try to make them thiner. I also remove all needles that are two years old in fall pine pruning as well as most downward needles below the branch profile. This results in a more open look to the tree. Your climate may not allow this.