As someone whos probably melted a lot of your slaves over the years i find the most effective counter is a combo of a gat bunker and chaos drone, use the chaos drone to draw in the terror drone then go after the deso, that being sayed your still going to lose some slaves. You need to remember the Sov is generally doing this to buy time. My aim in desoing your slaves is to allow me to get teched up for iron curtain and seige choppers. The best strategy is actually to pressure with a few early lasher/gat, especially if the sov goes radar first. the sov then has to deal with this so you can tech up quickly and get a disk. Id suggest going straight for the sovs power with 2 lashers and a gat. As soon as you get a disk i cant really get to your miners. You can tech up on 3 miners get a disk then get some extra miners.