A spray gun reservoir connector system. The system includes a reservoir lid, a spray gun inlet, and complementary first and second connector formats. The first and second connector formats are provided with one of either the lid or the spray gun inlet. The first format includes a plurality of retention structures each defining a capture region. The retention structures are collectively arranged in a circular pattern. The second format includes a plurality of lock structures each including a shim body configured to selectively interface with the capture regions. The connector formats are configured to provide wedged engagement between the lock structures and corresponding ones of the retention structures upon rotation of the spray gun inlet relative to the lid. The lid may include a spout. The retention and lock structures are radially spaced outside of the spout, and the spout may have an inner diameter of not less than 22 mm.