Further to the above, you need a squadron of at least 2 tanks in your command group.
I would typically suggest using the same weapons on both command tanks. Keep in mind, that Pask's
PE ability can be handy for Plasma-heavy tanks, greatly reducing your Overheat worries.
Personally, I love a Punisher Pask with an Executioner wing-man, with Plasma All-around. The punisher is too good to give up for Pask, but the Executioner plays a very similar role with the rest of it's weapons. Get Ignores cover on that unit and laugh giddily as you vaporize enemy units.
If the Knight Errant is the Knight without a Big Gun... Try again. You're doing it wrong.