3 packs and 2 chargers will do. You don't have to top the lipo's off when charging, just omit the last 15%, since it takes 50% of the charge time.

For instance, say you want 3500mAh flying capacity. Then buy 4000mAh packs and charge them with 8A (using a balancer) to about 3500 mAh. That will take somewhat less than half an hour. So fly, charge, fly, charge, fly charge.. you can fly continiously that way.

It's not really easier to achieve with glow engines, its cheaper. Unless you fly a lot, in which case electric will be cheaper in the long run.