What's the usual length (word count) for a novel?

My first book is about 90K words. With the revisions I've planned, it will probably go to about 100K. The second book, as originally written, is slightly longer, but not much.

The reason I'm asking is that I'm having a hard time recasting the second book with a change in protaganist. If it stands alone, it has to be Cestus' story. But I'm just having a hard time putting myself in Cestus' point of view.

Cestus is a great foil for Vadar, but not really a great protaganist. They are half-brothers, only a year or two apart, but raised very differently. Cestus was raised in the city and grew up to be a priest and a teacher. Vadar's mother ran away. He was raised on the plains, among a semi-nomadic tribe. Cestus tends to think things through and Vadar tends to do things. Cestus is willing to pitch in and help with almost anything, but he rarely initiates action on his own. He's fairly passive until towards the end of the second book. And I find I keep wanting to slip off to Vadar's point of view, because it's just more interesting.

So, maybe it's not three books. Maybe it's either one longer book, about 250-300K words. Or, maybe it's two books.

The initial conflict is resolved at the end of book one. But another, bigger conflict looms. I could (and probably will) bring that more to the front in the next revision. But, so far, the end of book one still feels like an end. Then, if I tightened up what I have for book two, eliminated or reduced some things, Cestus' story could be a sub-plot and the whole thing could go through to the end of the second conflict.

I just don't want to end up writing something that's too long.

I'm still thinking that the two-book idea might be the right one, though.

Cestus' story, standing alone, just isn't compelling. And I'm not sure I want to switch protaganist's in book two and then back again in book three.

So, Book One is about 90K Fantasy. Could grow to 100K in the next revision. Among other things, I'm going to put in more of the back story of the villain. It comes to a nice, satisfying conclusion. (I think so and so does the only other person who's read it so far.)

Book Two is also about 90K right now. Doesn't have quite such a satisfying ending. I'm sure that I can cut that down. How much, I don't know, yet. I know I can axe the "ending". There's some other stuff that I can--and should--cut way down. This is only the very first draft. I haven't even done a complete read-through of it, yet.

The outline for Book Three was always shorter than the other two. I could probably grow it. But I can also try to keep it short. If it's the last half or so, it should be moving faster towards the climax/conclusion.

So, maybe Book Two (combined) comes out around 150K (guessing, here). Then I really have to see what I can tighten up/cut.

The more I think about it, the more two books is just feeling right for this story. It's up to me to pull it off.