After reading a few comments and gathering my knowledge of Thracia, chapter 24x does not need to be visited unless you may need the warp staves the two dark bishops have, or the sleep and silence staves, then go to the chapter. Chapter 24 should give ya what u need to beat the game. I will always visit the gaiden chapter just for fulfillment.
Posting again, for Xavier's recruitment to be easier, have Tina steal the hammers from the lenster knights, and have pirn steal the killer lances, also have Tina steal the master axe and master lance, and have pirn steal the thoron tone and killer bow. Give the build ring to pirn before doing this so he can steal the lances. Also kill the freege knights with a magic user from the side of the wall (assuming you are funneling the knights at one if the doors) After doing that, you'll see Xavier's recruitment a bit easier but exhausts uses from the thief stave and repair staff. ( Safy will have repair the thief staff to get all the hammers, and master axe/lance)
MODEDIT: heh, months old doublepost