System 4 clamp sturdiness?

Hi! Looking to invest in a system 4 lap/table stand and I'm wondering from those who have it - how sturdy is the clamp attachment? I consistently work larger pieces on stretcher bars (14 x 14 in for example) and am wondering if it shakes or wobbles with the clamp + stretcher bars.

I've tried cheap alternatives from Amazon and they obviously haven't worked out😅can't stand that the canvas would wobble every time I pulled the needle through!

Insights + feedback appreciated!!