Changing the default blend duration?

My animation workflow is:

1. Record a take

2. Blend it

3. Repeat

To speed up my workflow, I use Ctrl+B shortcut to blend the most recently recorded take. However, I find the default blend duration too slow for my taste, and I almost always adjust it with the mouse to be shorter. This has slowed down my workflow, especially when I do arm animation (I want the arms to swiftly go into and out of a recorded position, and adjusting the fade manually had become a tedious repetetive chore).

Anyone knows how to change the default blend duration?

I didn't find any way to do this! Anyone knows how it can be done?