Saturn 5 to ugm trident II conversion

Hey guys i‘ve been wanting to turn my saturn 5 (the upper 2 stages specifically) into a trident slbm with launch tube and mechanism to „cold launch“ it just above the hight of the tube (ideally breaching blue tiles but those are details). I‘ll be keeping the test black and white colour scheme. Now here is my question: i‘m completly new to building tubes i think i understand the snot well enough to build the basic shape but i wanna know judging by the shapes do you think i need to order new...