Clutch shudder when setting off in 1st gear

[BuildCode]

I love this forum, just got my Yaris 900 miles ago!!!

My Yaris' clutch shudders when starting from a stop in 1st gear, and seems to mostly happen at 1500rpm. It doesn't at all seem like a 'low power' shudder, as if I were letting the clutch out at too low an RPM or something.
On my last car I would be totally off of the clutch under 1000rpm, I like to put as little wear on clutches as possible, which means starting off at lower RPMs and being fully engaged relatively quickly. What RPM should I be hitting the friction point of the clutch with?

The shudder is especially pronounced when I engage a little quicker than normal, and hold around 1500rpm while engaging.

Is my clutch still being broken in - was it not broken in correctly - what's going on!? I've been extremely careful on the clutch over the 900 miles I've had the car.



I've searched and only saw one other thread with this problem and it didn't seem to match my issue.