With iso, using thicker glass for the flare helps make it easier to do many things. If you're gonna put colored glass in there, use thinner stringers. It makes sinking them in easier, and there's less chance of cracking if the glass is more even. It would probably be good to start with clear dots/fuming. If ya start at the inside of the tube, and work your way around and out, offsetting the pattern, it helps to keep the tube evenly heated. Having a nice uniform dot pattern also makes it easier to sink in, and there's less chance of cracking.