A roller clamp assembly for adjusting the fluid flow rate in a connector tube of an infusion set is provided. The roller clamp assembly includes a housing to receive the connector tube, a plate slideably engaged with the housing and configured to rapidly compress the connector tube to provide a coarse fluid flow adjustment, and a roller wheel moveable engaged with the housing and configured to provide a gradual fluid flow adjustment. The plate may be a slide plate received by grooves in an exterior wall of the housing and that moves orthogonally to the connector tube, or the plate may be a shim plate that moves along an interior wall of the housing in parallel to the connector tube. Infusion sets and methods of adjusting fluid flow rates are also provided.