i made the bottle holder before i was able to weld, so i simply used 3 pieces of angle iorn and some bolts to hold it all together. there are a series of bolts the arround the base of the bottle to stop it falling through the holder.
when designing the bottle holder you should consider where and how you are going to place the light bulb holder. the light bulb should be about 5mm to right against the glass of the bottle, it needs to be close to conduct heat. if you plan on using a cylindrical bottle you may be lucky enough to find a section of steel pipe or something..