Disclosed herein are fluid distribution methods and assemblies for supplying fluid to test assemblies. One embodiment of a fluid distribution assembly comprises at least two input lines each configured to supply a fluid. A source selection component is connected to the input lines and configured to receive the fluid of the input lines and select from the fluids a target fluid. A range selection component is configured to receive the target fluid and to select a flow range of the target fluid, outputting the target fluid to a flow component comprising a first flow adjustment component having a first flow rate resolution and a second flow adjustment component having a second flow rate resolution. The range selection component is configured to selectively output the target fluid to one of the first flow adjustment component and the second flow adjustment component based on the selected flow range.