A trial humeral prosthesis may include a trial stem for implantation into a humerus, and a trial proximal body configured to couple to a trial articulating component. A plurality of trial spacers may be configured to couple the trial stem to the trial proximal body, the plurality of trial spacers including a first trial spacer and a second trial spacer. The first and second trial spacers may each include a proximal post and a tab extending radially outward from the proximal post, and a distal body having a larger outer diameter than an outer diameter of the proximal post, a slot being formed in the distal body. The slot of the distal body of the first trial spacer may be configured to receive the tab of the second trial spacer when the proximal post of the second trial spacer is received within the distal body of the first trial spacer.