You definately need dust collection close to the source, but this type of collector will clear the finer dust particles that escape the primary DC. The ceiling collector should be run continuously, and left running for some time after you leave the shop.
When I built a similar collector I was able to utilize a surplus computer main-frame blower. I also use two filters at the inlet and a third filter at the outlet. Two inlet filters turned out to be a good idea, because the first one doesn't catch it all. The 3rd one keeps the inside of the box clean on those occasions when I forget to turn it on. Sad to say I, too often, forget it.