With any House and the Ix Subhouse, Build a duplicator and one of your strongest units (Ordos:Deviator, Harkonnan:Devisator, Atredies:Sonic Tank ). Build two Adv. Carryalls, and drop them near a base, On rock..I've made that mistake...Deploy the Duplicator, and simply duplicate the unit you brought with it, and just send the units in, not the real one..so you get a free supply of strong units that build in seconds. Another trick to use on the Ordos is to duplicate the enmies laser tanks..The duplicate laser tank will shoot the sheilds will refract and blow both of them up. You didn't pay for your tank so no shead tears. The Laser tank is also great to mass produce..as it is fast and will move away so you can make more.