Full body FPS

I'm working on an FPS that I want to have full body rendering in. I've already got arms and feet rendering and animating really nicely, but I want to take it all the way. I have a lot of programming experience and experience with basic animation in Unity, but I'm not familiar with all of Unity's more advanced animation tools. What would be the best way to accomplish aiming? I've tried blending between an "aim_up" pose and an "aim_down" pose, but the blending messes up halfway between the extremes, and adding intermediate poses hasn't helped. I'm not liking the results of seperating the arms and body so far either, because I'd like the shoulders to be visible for VR headsets. Is there any feature of the mecanim animation system that I should be aware of that might help accomplish this? I'm fine with the arms not being perfectly fixed to the camera when hip firing as long as the gun is pointing in the same direction as the crosshairs. For ADS I'm thinking I'll end up having to either interpolate to a second camera position, or just rotate the entire upper body independently anyways.

 

Check out the old legacy locomotion asset system on the asset store for reference. (I think it's legacy, may be mecanim) It uses a look at (thingie) I think it may be layer mask which blends the animation upper body out and blends the look at cursor with a falloff which rotates from the waist up. It's pretty cool.
I also saw something very similar in one of the older Unite talks.
All just from memory, sorry I don't have any specifics. But I know they could be used in a fps view to aim so it's relevant.

 

What do you mean it "messes up" halfway between the blend? That's the canonical way to do aiming.

It does sound like the legacy bone system would help here because you can have full control over all of the bone rotations so you could programmacally do something like a "look at".

 

It turns out it was a problem in the way I was sending the parameter values that made it get stuck blending in a weird way. I fixed that now and it's working.