CCS

Okay I ended up with the following settings seem to be working well for the Altezza TB:
 
Proportional gain: 4.75
Integral gain: 0.005
Derivative gain: 35
Max clamp / min clamp 95%
I started out with higher values for all of the gains, but found that I had the throttle plate fluttering after a sharp opening, and also when held steady state at 100% throttle the TPS reading (and throttle angle) was fluctuating.
So I held it at 100% throttle and kept reducing derivative gain until it stopped fluttering at steady state 100% throttle.
Then quickly flicking throttle open to say 30%, reduced integral gain and proportional gain until the throttle plate would stop fluttering.
Since it was working with two variables I'd reduce one until it stopped fluttering then see if I could raise the other, the values above seemed to be the combination where I could go the highest on both.

Based on observation:
Proportional gain determines how quickly the throttle plate moves to reach the target initially.
Set to a low value, and it will take a few seconds for the plate to respond to changes. (will feel laggy) Set too high, and it overshoots and needs to overcorrect and causes fluttering.
Integral gain seemed to be how aggressively it tries to fine tune the angle once it's reached its target. If you snap the throttle open quickly to half way and it flutters, reduce this.

Keeping in mind you want the highest values that do not cause flutter for best response,
If you setup a screen on the laptop to monitor FPS main/sub and TPS main sub, you can see if the throttle plate is fluctuating compared to FPS position easily. Although sitting with the TB in front of you where you can watch it also helps.
It seems to be pretty good now, good throttle response but minimal flutter. I've only tested with the engine not running so far though.
I'll see how it goes when I've finished all of my wiring.

So far though I'm pretty happy with how it's working! Looking forward to having the car be a bit more drivable at low throttle angles.

In case anyone is trying to do the same or something similar. AiM released a new feature. Now you can build your own CAN message.
CAN DRIVER BUILDER The CAN Driver Builder is a utility included in RaceStudio3, intended for developing a software driver capable to read a CAN datastream coming from an ECU or a different device. The driver produced can be used on one of the following devices: MXG, MXS, MXL2, EVO4S, EVO5.
http://www.aim-sportline.com/download/software/doc/CANDriverBuilder_100_eng.pdf