In certain embodiments, a linear adjustment mechanism includes an adjustment plate, an adjustment nut, and a holding plate. The adjustment plate has an exterior-threaded section that engages with the adjustment nut, a mounting-bolt opening, and a clamping-bolt slot. The holding plate has a horizontal section having a clamping-bolt opening, a vertical section connected to the horizontal section, and an adjustment-nut opening. With (i) the adjustment nut engaged with the adjustment-nut opening and the exterior-threaded section of the adjustment plate and (ii) the clamping bolt inserted within (a) the clamping-bolt slot of the adjustment plate and (b) the clamping-bolt opening of the holding plate, (1) rotation of the adjustment nut on the exterior-threaded section of the adjustment adjusts the linear position of the adjustment plate relative to the holding plate and (2) rotation of the clamping bolt secures the linear position of the adjustment plate relative to the holding plate.