I use 0.093 inches. Upon cooling, the weld sucks back the component by 33%, approximately. This means that the final gap between the components is 0.062 inches.
You need to gap the pieces being weld in order to achieve a good root penetration, hence "melt" to the parent material. Hope this helps.
Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada