There's a registry key to control the delay:
http://www.sevenforums.com/tutorials/40425-taskbar-thumbnail-previews-change-delay-time.html

Do you mean the animation?

I believe there's no way except for completely disabling the taskbar animation.

Great. I'll include the fix with the next version.

Creating a decombined button group without labels is tricky.

The solution is very hacky, let's hope it works for all cases now.

Second attempt:
https://www.dropbox.com/s/1enslsmxx4qzgfp/7tt_setup_4.2.7.2.exe?dl=1

I believe I fixed it.
Please try the following version and tell me whether it works as expected (second attempt):

https://www.dropbox.com/s/1enslsmxx4qzgfp/7tt_setup_4.2.7.2.exe?dl=1

Well, the tweaker mostly offers options that are not available via registry tweaks or other tools. It doesn't touch the registry.
That's also why it's required to to be running to use the features it offers.
Implementing this option would be an exception, and is not likely to happen.

> First, many people who use your awesome tool (including me) wasn't aware of such a nice feature.
It's very easy to Google.

> Second, using multiple tools for such small features would be a mess.
The tools in the link you posted isn't required to be running for the change to take place. In fact, it isn't necessary at all if you modify the registry manually.

> Third, your tool is all about the taskbar and this feature belongs very much in your tools purpose.
It's already complicated enough. In the current design, there's no place for such options, and I wouldn't like to complicate it even more.