I haven't had any luck with chronoboost on the minimap.
Yeah, it's down right impossible. If you tried it consistently you'd probably be chronoboosting the wrong building half the time.
I've tried it on the minimap for expansions where the Nexus is the only thing nearby but even that doesn't work well cause it takes 3 or 4 clicks before you're actually targeting a building.
This just doesn't work in my game. Nothings happening, when I C-Click + Leftclick on the icon in the group.
Didn't think that worked, must have been patched at some point. Too bad, would have made chronoboosting a lot easier.