First lets clear up this one little thing.....
The very first Castaic trout was all wood, and jointed in the middle. Very cool lure which some trophy bass guys swore by..... but a collectors item now. I have one in mint condition, but it will stay that way.
Then they went to a Hard foam type of head, with a soft plastic body. This is the one I use.
Now I hear they are changing designs again. Of course I will be nervous about that until I use one, because I liked them just fine the way they were.

But anyway, I have only caught one good bass, a 13.2 lb'er, on the 8" paddletail Castaic, and it had been highly modified, by getting rid of the single hook, and adding a treble hook (pro-rigging).
All of the rest of my Castaic trout bass were caught on a regular 9" soft trout (with hard foam head and lexan diving lip).

I do not modify it, but sometimes you have to tune them by slightly bending the eyelet to the left or right according to the direction it tries to swim. (note: be careful not to scratch the eyelet, as this will damage your line while fishing.... just rap a piece of cloth around it before grabbing it with needlenose pliars)

My feeling on trailer hooks is this.....
I know a lot of guys will tell you they have got a lot of bites and didn't hook up, and that this lure has a low hooking percentage..... Hmmmm. I am very sure that a lot of those so called "bites", were just what I would term, "swats" or "nips". It seems that often a bass will not even intend to eat the lure, but rather just wants to get a feel, or a taste, or see how this possible meal reacts to being hit. There is also the thought that they are trying to stun the trout first, so that can spin back around and eat it more easily.
But the bottom line is, when big momma finally decides she is going to eat that trout, she will absolutely inhale that thing and your hookups will be about 95% or better !!!

Anyway, two things in closing:
I do change my hooks out with 2/0 Gamakatsu round bend trebles (bronze)
.... and remember to fish this lure very, very slowly.... just fast enough to keep it under the surface and to make the tail kick a little bit.

Good fishing to you,
Fish Chris