You might not find Riflemen + Warriors viable unless you have 2-4 armies' worth at a time.
But if you really insist on using Riflemen + Warriors, you might as well start by taking out as many Shock Launchers, Machine Guns and Flamethrowers as you can. Maybe it gives your Warriors some extra time to stay alive (it's very unlikely any of your Warriors will survive a head-on attack).
If you can handle it, you can smoke the two types of troops towards the HQ. It's not going to be very easy to execute, considering that smoking Warriors to HQ and smoking any other troop towards the HQ is very different in execution. This might give your troops a bit better of a chance at the base, if you have enough GBE to shock everything around you.