Abstract: There is disclosed a customizable system and methods of use for manufacturing and testing a variety of pre-sutured allograft tendon constructs sutured according to a variety of stitching patterns and featuring a variety of tissue lengths and types. One embodiment includes a triple-channel base having first, second, and third longitudinal channels extending between first and second ends of the base, as well as a plurality of tendon-manipulation accessories. Each of the tendon-manipulation accessories includes a locking-base assembly for selectively securing the accessory to the base such that the multiple tendon-manipulation accessories may be secured to the triple-channel base in a variety of custom arrangements suitable for preparing the variety of pre-sutured constructs and/or for pre-tensioning or testing the variety of the pre-sutured constructs. Other embodiments are also disclosed.