I have an evolux 82ed with asiair, eaf, 2600mcp, autoguiding and its just over 5kg. It's fine in no wind but gets knocked quite a bit from even a small breeze. I get between .8-2sec depending on where it is pointed. Also I got a second counterweight.
Tried just on 5kg when I had mine (ASKAR FRA400, 2600MC, AA+, small guiding setup). No idea whether it was the weight, or quality of the mount (guessing it's the latter) but I never was successful with it.