I think that cluster feeding works the best with newborns who are truly hungrier and need to nurse more often. With a 6 month old, I wouldn't introduce cluster feeding, there is no point in that, especially if you are feeding him solids. How often do you nurse during the day and does he still wake up at night for a feed? Are you concerned that he takes too little of your milk in general?
If he doesn't wake up at night you may want to slowly eliminate a dreamfeed by moving it earlier each day or every other day by 15 minutes.