Rib Cage IC

I was browsing HBT looking for a faster way to cool my wort. There are times in the summer where it has taken me 75 minutes to cool from boil to pitching temp, and that is just not fast enough. I have plans to make a prechiller to help combat that, but then I ran across this thread.

http://www.homebrewtalk.com/f51/diy-interwoven-rib-cage-immersion-chiller-106415/

The OP calls it a Rib Cage Immersion Chiller (RCIC). My current IC is only a 20' length, and during the spring/fall/winter it doesn't do to bad, but I'm still running times of about 40 - 45 minutes to reach 70F. Many of the people in this thread claim to have gotten down to under 15 minutes to cool 5 gallons.

With a prechiller added, other claim under 10 minutes for 5 gallons. I'm thinking I'm going to try out a similar design, and retask my current IC into the prechiller portion for the warm months.

There are several other alternate takes on the RCIC, and I think I'll attempt the following:

I like the design, it has the dual coils both being fed cool water at the top, split with a T, and then the outflow is collected with another T at the base, leading out with a single outflow tube. The in/out single tube will need to be a larger diameter than the coils themselves I would think to keep from a chokepoint slowing the flow of water. I plan to make something similar.

Here is another one:

This one is quite a bit more radical and involves quite a bit of work to make, but I bet it cools down faster than blazes given that each coil is being feed cool water. To much work though.

Let me know what ya'll think.