Hi all! I'm new to gardening, and to this site, so I'm hoping that someone here might be able to shed some light....

I have a block-wall fence in my backyard with a trellis attached to the top of it. This was done by the previous owners to partially block the view of the plumbing company behind the house. Since the owner of the company parks his trucks behind our house and is now storing empty toilets against his side of the trellis, we need to block the view completely. I plan to plant crossvines, but I'm not quite sure how to space them. The block wall is 5-6 feet tall, and the trellis above adds about another 2 feet. I want to train the vines to grow up the wall and to spread over the trellis (as opposed to covering the entire brick surface AND the trellis). I was thinking about planting them about 10 feet apart--I'd like the view covered ASAP, but I don't want to create a problem in the long run by planting them too close together. Any insights would be greatly appreciated!