The Coast Guard only certifies boats less than 20 feet for HP and load capacity. However, Code of Federal Regulartions Title 33, 183.35 States that the maximum weight capacity of an outboard powered boat shall not exceed 1/5 of the maximum displacement and the weight of the boat. The maximum displacement is defined as the boat sunk to the level in calm water where no water comes aboard (usually over the motor well) and with only one hole up to 3" sealed. (ie the hole where steering and cables exit the hull to the motor well. There is no federal enforcement of weight capacity, but some states have cited boats for being over loaded.
It depends on the conditions and judgement of the skipper as to how to load his boat. Also remember that the previous federal standard of the "weight of a person" was 140 lbs, established in 1942. The current average weight was raised to 185 lbs after the sinking of the Edith Allan.
So I would say that 6 to 8 would be the max I would put aboard a CD 25.
Yes, you could use the boat as a 6 pack charter boat--but I think that in heavy seas, this would be marginal. I also base some of this on the fact that the CD 25 has a self bailing cockpit and an almost watertight cabin.