Just a warning, 8 wounds for 340 is not very tanky at all. That's his biggest drawback, so you need to pick your spots. That's why it kind of works well with Seraphon, you can flood the board with skinks and hopefully get onto objectives and hold on for the first couple of turns so you can maximize the turn or two that the Prime is on the board. It's not a perfect plan, but it can work.