im taking on a new client and I'm thinking about setting up 4-5 niche sites to act as tier 1. But I want to rank these sites in their own right each for a different sub-niche of the clients main niche. Idea is they will end up being very high quality sites linking to clients site and if they rank I can also drive leads to clients site and/build targeted mailing lists from them. But also it means I can build links to those sites a bit more aggressively without directly harming clients site. What are your thoughts on this strategy?