I have identified the following as Callaway Co judges around the period described:

Joseph Flood
Sam B Collier
George Bartley
G.E.O. Hockaday
I.O. Hockaday
Thomas Ansell

pulled from Fulton, Missouri 1820 - 1920, By Carolyn Paul Branch, Longbranch, 2010

From History of Callaway County National Historical Press 1884 http://cdm16795.contentdm.oclc.org/cdm/ref/collection/mocohist/id/144851840

County court justices. -George King, 738; Milton Cleveland, 731 ; John S. Henderson, 288; Isaac Branham, 360.
1842
County court justices.- William Robinson, 579; Joseph Fisher, 180.
1844
Justices of the county court. George King, 640; James McClanahan, 753; E. M. Overfelt, 81; M. Cleveland, 423; George B. Hop- kins, 820; Isaac P. Hone, 11.
1846
County court justices. -James Baskett, 632; John A. Burt,
1848
County judges.- J. McClanahan, 1,050; G. W. Morris, 969; F. G. Nichols, 488; T. S. Ferguson, 386.
1850
County judge.-N. Bodsworth, 633; John A. Burt, 981. 1852.
1852
County court justices.-M. Bright (W.), 749; William H. Bailey (W.),
1854
County court. -W. Carrington, 881 ; G. B. Hopkins, 763.
1856
County judges. - Henry Cave, 823 ; Michael Bright, 815; Charles A. Ming, 1,136; Joseph Flood, 1,070.
1858
Justice county court.- G. B. Hopkins,--- W.R. Kidwell.
1860
1864
Judge county court.- John W. Veitch, 600; H. F. Renoe, 712; B. F. Bailey, 199 ; Charles A. Ming, 167.
1874
Judge county court.- Henry F. Renoe, 787; Hugh Tincher, 1,651.
1876
County judge.- Elijah V. Dyson, 1,290 ; Samuel B. Collier, 1,265; Isaiah 0. Craighead, 756.

As you can tell the list is long but some sleuthing and WAGs leads me to putting Joseph Flood or HF Renoe highon the list. George Bartley comes in a close 3rd.