clip on aero bar question

Yes...they can make a big difference, both in speed and in comfort. For road bike applications (like your OCR), I recommend the Profile Jammer bars. http://www.profile-design.com/2006_product_pages/aerobars/jammer_gt.html

The short reach is good for not stretching you out too much on the relaxed seat angle of your road bike. And as for the gut, they can be adjusted high so you aren't leaning over so much. This will lessen the aerodynamic advantage, but it will still be better than riding on the drops. 

I have a pair of clip-ons on my road bike, and I love them!!  I might ride 5 - 10% on the hoods/drops for the entire ride, becasue I am much more comfortable on the aero bars.  I defenately am glad I spent the extra money, I feel that they are TOTALLY worth it in every way.

Benihana

I am 6'-2"  - 230 on a good day and I have a gut. ( that is slowly getting smaller)   I ride an OCR-3 and I have the Profile airstrikes on the bike right now.  I almost always ride on the hoods as well.  This is the first summer I am trying the aerobars on the bike.  Right now my seat is about 1-1/2 to 2" above my base bars.  At an easy pace I can stay in the areobars for a good distance but due to the type of roads and traffic it doesn't last for more than 10 minutes.  When I ride hard, I find that I can not stay aero for longer then 2 to 3 minutes due to the increased in breathing effort and the gut factor.   There is a noticable increase in speed for less effort while in the bars.  As Jim has stated you can start in a move relaxed position and more down as you fitness level increases.

Thinking back, I should have got them for  last season but it was my first season training and did not want to go overboard buying stuff.   Boys and there toys.

Mike

I'm 5'-7", 185lb, barrel-chested with wide shoulders and also have trouble getting too low on my aerobars without restricting my breathing.  I have my elbow pads pretty much level with the height of my seat.  Not a perfect Dave Zabriskie-type flat-back aero position, but it works for me and my physique.   I'm very comfortable for long distances.  With a history of carpal tunnel problems, I also like to be able to take the pressure off my hands and wrists on long rides.  I typically need to shift to a higher gear when I get in the aerobars, so I also take that as a sign that my set-up is working okay.

The first set of aerobars I bought were not adjustable length-wise and did stretch me out too much (no doubt accentuated by my relatively short arms).  The set of Profile Design Carbon Strykes I have now are very adjustable -  I've got the hand grips pulled back to just in front of my brake hoods, realtively close to the geometry of the jammer-style bars that Jim suggested.

Aerobars definitely do help, but for us bigger guys the trick is finding the compromise sweet spot where you have the maximum aero advantage without restricting your breathing.

Good luck

Mark

You can expect a good 1mph, maybe more if you are set up ideally.

I picked up 1-2 mph almost right away. 

Mark