To determine the exact dimensions for a rectangular spray control we need from you the exact dimensions of the two branches S1 and S2 and the radius of the rounded corner. The minimum measure of both legs is 60mm.
Attached is the formula to calculate the circumference of the spray control. For this calculation you can use the spray control tool below. ((S1-(2*r))*2)+((S2-(2*r))*2)+(6.2831853*r)=Circumference of your required Spray Control