The 1874 RLDS edition accidentally omitted the adverbial use of far here in the phrase “far more tolerable”. The 1908 RLDS edition restored the far to the RLDS text. The text has many examples of the standard English comparative form “more ”, but there is one more example of “far more ”:
The critical text will maintain, of course, both instances of the comparative construction “far more ”.
Summary: Maintain in Alma 9:23 the use of far before more, an example of the quite permissible comparative expression “far more ”.