I've done the duct tape on the insides of the tires thing and it does work to significantly reduce the ballooning. The downside is that the tape usually lets go at some point; and if this happens before the tires are worn out, you're screwed. I had considered using bead locks just because of this.

As for boiling the tires and wheels to get them apart, I don't know if it will work. I do know that it will make the wheels softer, possibly making them more susceptible to warping. I've often boiled graphite or hard plastic parts to make them bend more and less likely to crack. Usually the suspension arms. This is why I don't boil my wheels when I dye them. I just boil the water and then pour it into a bucket and dip the wheels for a little time as possible. The dye doesn't go as deep, but the wheels don't get too soft either.