Upholstery issue

[NJ C10 Guy]

This seemed like the only fitting forum to post this. If it's in the wrong spot, please move it to the correct one, mods.

I have put a lot of time into my console (way more than I imagined). Anyway, I am stuck and I am in the final stage. I have the the inside and outside upholstered (pics attached). I tried wrapping all the way around with 1 piece of vinyl, but it wasn't working out where the sub was. I could not get it clean no matter how many relief cuts I used. I decided to cut and glue the inside and outside pieces separately, and now I have the edges to finish.

I tried to use sprinkler line, which kind of works but it's got a natural bend and it kinks when I put it on, which you can really see in the second picture. Heating it only does so much. There has to be a product available that will suit my needs, I just don't know what it is. Any help is appreciated. Thank you in advance.