Yeah Just double checked that...
So with the Original 16Ap that becomes null(6Str, 2Cap, 4Boost, 4CA) 20-26 = 12-18, and Kensai Mastery 1Ap per tier correct? That drops the total from 12-18 to 9-15. 9-15 may not be enough for Juggernaut, but you could go a step further(with this build) and lose WF; Tactics II for 4Ap and if worse really came to worse ditch Fighter Strength III and settle with 36Base Str.
Which would leave;
9-15 + 4 = 13-19 or 19-25Ap which would then perhaps leave room for extra Action Boost I and II.
Its going to be tight Im well aware, but hopefully worth it.
To be quite honest I wouldnt even mind losing Fighters STR II and III, sure Id lose +1 to-hit and damage but Id gain 10Ap.