Simple question; what happens if you build all your back links before google has indexed your site? Can you get away with building massive links fast then?
I am not sure why having a lot of backlinks out there is a bad thing any time regardless of how fast you made them.
Google already will take close to one month to index your main site unless you ping it and bookmark it. They surely aren't going to index hundreds of backlinks at once either. They will come in steady as the spider's crawl.
According to Google Backlinks are given by sites if your content is useful but if an unindexed site gets a lot of Backlinks then it may look suspicious.