The OCR3 has a triple on it with 52/42/30 and a 12/28 rear cassette. That climbed Ventoux which is not that steep but goes on a bit. I did need that 30/28. Now locally on on 10/12% hills and the odd steeper- I also use the lowest gear. Now Boreas and the TCR have a compact double. 50/34 and a 12/27 cassette. Those hills I struggled up with the OCR in Lowest gear----I now struggle up with the Compact gearing on the other two. I often do a ride on the compact gearing taking in a 3 x 1 mile hills. 1 @7.5%, 1 @ 10% and one at 16%. The 16% did take some mental preparation to tackle and I do not do it very often (Swop it for a shorter 15%) as it is hard. But not bad- 3 good hills in a 20mile ride---+ the other up and down bits aswell.
Not saying it will not bother you but in my case- the loss of that 30t triple ring had me worried at first. I started getting confidence in my climbing ability by doing the 7.5's before tackling the 10's- then the 12's. What convinced that the 16% was possible was that the week before I had done a 12% with a 25 mph headwind. It's possible. The bike is lighter- it rolls better so not using as much energy and the climbing ability of the lighter frames is tremendous. Whether that is mental or not-I do not know- as my top speed on the flat has not increased- I don't think it is solely the bike.
Then if you do get the bike and not find you have a low enough gear-Rear cassettes are easy enough to change-----Or failing that- a change to front chainring sprockets is always possible.
Edit------ This is a new bike and if you talk kindly to the LBS- They should be able to sustitute a Mountain bike Crankset for you. A 48/36/26 should be possible- but not certain that the quality of the only one I can think of (Deore) would be as good as the Ultegra set up. But there are other Good quality non OM crankserts out there. And--It would be possible to run a 9 speed set up to get a lower gear- but I am just wondering if that is what you do need. If it worries you that much- The change the crankset from new and perhaps some of the MTB riders can come up with a lower geared quality set that they could recommend.
And for 10 speed and lower gearing- look at one from Harris cycles. The IRD 10 spd cassette-11/32/ or 11/34. Expensive and will also require a rear derailler.
http://sheldonbrown.com/harris/k7.html#10