Hi, and sorry for the late reply. There is no option right now for that in the dashboard. And yes that is true, that's how you will show the inline buttons on home/index page but by modifying that file on the next update your modifications will be overwritten.
About your tests, I'm not quite sure you have it right. The inline buttons on posts/pages load under 1s (usually 150-200ms) cause all it has to load is a sprite image with all icons.
And if you were talking about the bars, well the bars take arrown 5s to load being generated from our server. That's if you dont have any other scripts slowing down your loading events.
I really don't think you that the inline buttons load in 20 seconds, that is quite a huge figure and you should show us some stats, or send us a url where we can see the plugin in action and test it.