Plumbers tape is great- but it's overkill for this job. The foam padding is fairly smooth on the surface; it would slide into the suit easily. It's the bulk and increased diameter of the wrapped legs and arms that would make it a tight squeeze. I have a trick for that though: I'll attach some lengths of string at the ends of the wrist and ankle padding. Then I'll feed the strings through the sleeves and pant legs, then I can pull them in-- like threading a needle.
I'll experiment with thicker and thicker layers of padding until a good filling shape is achieved. Then I'll tape them with small bits of clear postal-grade packing tape, (that type seems to be the stickiest) and make the final insertion.
This is all simple stuff. The hard part is getting a Haywood Floyd head sculpt. I have researched the earphones, mic, and cloth bonnet worn inside the helmet. Now it's just a question of either sculpting it myself, or having a much more professional job done by Ulli Pekka at 'From Russia With Love'.
If enough of us get together and commit, Ulli Pekka can produce an amazing 3D-rendered sculpt at a fair price split between all of us. I would like two variations, so Haywood Floyd can be displayed without any head gear too. I would love to make a diorama with Floyd sitting on the moonbus in the window seat, with the surface of the moon visible out the window, drinking coffee, eating his ham sandwich, looking at the monolith photos. (I meticulously reconstructed them, see below)
During the process of reconstructing these, I discovered that there are NO surviving flat images of the original prop photos used in the film. The bottom two I had to reconstruct from scratch just by referencing the film. However, the top two are a different story. I knew Kubrick must have used real fly-by photos of the moon taken by Ranger 7 in 1964. Therefore, I had to search through literally hundreds of genuine photographs of the surface of the moon, and I eventually stumbled upon the actual photos that Kubrick used. I isolated the areas that were printed in the prop photos, then I reconstructed the survey graphics on top of them... just like he did.