The bent sides which I received from LMI had quite a fair bit of spring back.
So I use an Aluminium pipe coupled with an heat blower, to correct the spring back to the plantilla shape.
I was using a Hauser 37 plantilla which is smaller than the Ramirez plantilla.
The sides were bent to the Ramirez shape as pointed by Les.
So at the same time I took the chance to correct the plantilla shape too.
After correction by the heat pipe
My heat pipe setup
Although the sides were bent by LMI, I did learn the feel of how to bent the sides by hand when I corrected the curvature.
I did learn an important lesson of how to bend the side by hand.
With this experience I would be more confident to bend my sides for my next build (at least for IRW)
I am not sure how the guitar would fare in a tension spring back mode.
But I didn't want to take the chance.
Moreover, with the bending correction, I did pick up an important experience of bending the sides by hand.
So that is why I went ahead and correct the spring back to the plantilla shape.
Best of luck for your build!
You would love the experience of building guitars as I did.