When making a new, high level Mastermind type creature, do you prefer them to have lots of hit dice to reach the appropriate CR or to have fewer HD but add class levels?
For example, let's say I wanted a CR 16 monstrous humanoid to fill a Mastermind role. Let's say it'll have an 18 INT either way.
For straight HD, the chart suggests a CR 16 monstrous humanoid should have about 21 HD. This gives:
- 115 HP
- +21 BAB
- +7 Fort., +12 Will, +12 Ref.
- 11 feats
- 168 skill ranks (plenty to max anything important)
- Any special features such as spell casting or spell-like abilities. Let's assume it can make extracts as a 12th level Alchemist, for this argument.
On the other hand, we could give it 13 HD (about CR 10 by itself) and 6 levels of Alchemist (or something, assuming whatever class stacks well with its other abilities). This gives:
- 98 HP
- +17 BAB
- +9 Fort, +13 Will, +10 Ref (I think)
- 10 feats
- 152 skill ranks (and a lot more class skills)
- Some special features
- Alchemist abilities up to 6th level, plus another 6 levels of extracts (to bring it back to 12).
So I guess my question is, which makes a better Mastermind monster? (This is just one example. You could easily replace Alchemist with just about any other PC class, though Masterminds tend to be casters of some type.) Would the creature type have much effect on your answer? I used monstrous humanoid here, but I'm thinking more about an intelligent ooze.
Thanks.