Here are a couple older studies, however it will help you improve your search and may provide more answers to your questions. Good Luck -Paul
Multielectrode recordings of tibial nerve H-reflexes at various triceps surae muscle sites in the right and left legs. This multielectrode recording technique indicated that spinal responses evoked in the triceps surae muscle are symmetrical in humans.
Burke J.R. Electromyography and Clinical Neurophysiology [01 Aug 1997, 37(5):277-286]
The relation between handedness and the Hoffmann (H) reflex recovery curve was studied in normal subjects. In right handers, the H response recovery curve from the right leg was significantly lower than that from the left leg. The opposite finding was obtained from the left handers.
Uner Tan International Journal of Psychophysiology Volume 3, Issue 1, July 1985, Pages 75-78