Not knowing him, I couldn't really know what to expect.
And not being the fan type I don't actually check his site with any regularity.
I read the estimates about 2 weeks ago and I read some blog entries. I might have gotten the 750K from that. But I'm encouraged to hear at least 300k although from the writer perspective, it seems that longer or shorter would be easier.
As for YA. An awful lot of YA is close to 200k. Case in point Green Riders call. I could go on but would be tedious. 90k sounds more like tweenie novels...
But I will take your encouragement and hope you are right.