Shaft suggestions? One club (6i) golf, need low launch!

[scottgerweck]

So I'm a speedgolfer. I'll resist the urge to prosthelytize, though it's tempting. Most speedgolfers play with 4-6 clubs, but I use only a 6-iron (yes, even for putting) for strategic reasons.

Here's my question: I'm looking to build a 6-iron which will give me maximum options while playing with just one club and am specifically looking for suggestions for a low-launch shaft that will handle the occasional need to really try to kill the ball on par-5s and long par-4s, and also help keep the ball a bit lower in windy conditions.

Some background on my game: I'm generally a 4-5 handicap with a full bag, and perhaps a 9 while using just a 6 iron. I can get away with using only one club because I'm a long hitter (thanks to being 6'4" and flexible) and have a pretty decent shotmaking skills. My general 6-iron distance is around 180 with my 1"-over-standard Mizuno MP-67's with dg-300 s-flex, but I can hit that club 200 or more if I need to and manage to strike it properly while swinging accordingly, though the flight is always high when I swing like that.

I'm using a TM RAC forged 6-iron head for this new build, as I hit that head maybe 10yds further than the Mizunos and it still gives excellent workability and the (relatively) narrow sole necessary to hit flop and bunker shots with a 6i. I'll go more like 2" over standard so I have a bit more leeway to stretch out and hit it when I need to (I'll choke up an inch most of the time), and certainly an x-flex. Any suggestions from all you shaft fiends out there? The goal is maximum stability with as low and piecing a launch as possible.

Thanks!