I prefer the 1+9 dilution of Ilford Rapid Fixer for prints. Handling larger prints and trying to keep the fixing time in two baths plus drain time to under 60 seconds is just too hectic. For RC prints, which don't have the washing problems of fiber-base papers, there's no reason not to use a longer fixing time and a weaker dilution. Since the capacity for both the 1+4 and 1+9 dilutions are the same, it is actually more economical to use the weaker dilution. If you are processing for optimum permanence, do use two fixing baths.