Can you just tape it down so it holds its shape? That's what I tend to do with disc covers.
Also, if you adjust the tension of the plugs, it moves the inny/outty bits.
Yeah, I'd still suggest having a play around with how tight you make the plugs. I found you could tweak out most of the ripples by slightly rotating it or adjusting how tight the plugs were.
Can you just tape it down so it holds its shape? That's what I tend to do with disc covers.
Also, if you adjust the tension of the plugs, it moves the inny/outty bits.