I don't have the answer for you. What happens when you go to the 32 up front and run a smaller ring on the cog.??

I would think there is a combo on your rings that would work for you. You just have to find it and be prepared to lock in before you need it. Sometimes it's all about knowing what gear you need in advance and timing it just right. You say it's a short burst so I'm not so sure changing rings will solve your issue.

No offense here, I don't know you but, another way of looking at this would be strength and endurance. The stronger you are you can drop the chain down the cog out back and use strength to get you where you want to be.

Also, you have a great group set. But, the cog has 11 gears, I do believe, so it's relatively wide. From what I've read about that cog, it doesn't get much better. Lots of bike companies will put on an Ultegra group set and use that 105 cog in the back. They last forever and people love them. So I don't think you have to worry about cross chaining for short bursts on the cog. The chain, well.... I don't know.

These are my thoughts. Others with much more experience will chime in soon, I would suspect.