[No Pattern] Not sure how to go about modifying T-shirt Sewing Machines Parts and Sales in Los Angeles

I’m sorry in advance because this might be a confusing question.

Basically I am sewing and then gluing plastic into a T-shirt. I am going to use Aleene’s fabric glue (the stuff for plastic to fabric). I’ve used it before and know that it works good for sweatshirts, but I’ve never tried it on a T-shirt. Does anyone know if it will make the shirt feel/look lumpy? Will it affect how the shirt moves a lot?

I am also looking to put a lining in the shirt, that way the plastic won’t be uncomfortable for the wearer. Unfortunately, this T-shirt doesn’t have a side seam so don’t know where I would sew the lining to cover the plastics on the inside. I was thinking maybe there could be an iron-on fabric that I could iron around the plastic (but not on the plastic because that’d melt it). But again I don’t know if that would make the shirt oddly lumpy. If I should sew on a lining, how do I hide it so that the stitching isn’t noticeable?

Sorry if this is hard to follow, and thanks in advance!