FWIW I have Jim’s kit. If the neck section is an issue with clearance, so be it.
I tried unsuccessfully to make a similar item to stretch over your head from PolyTek PT flex liquid rubber. I had several attempts, spending around £150 plus countless hours attempting it. Whilst it would be achievable, I’m not spending any more money attempting it.
I made a basic O shape, with a inside diameter of my neck plus maybe 20mm and about 6mm thick. I couldn’t stretch it over my head without it tearing, and that was with it being fully cured.
Also, whilst I’m waiting on confirmation of the proper paint code, matching the paint to the pigment dye of the rubber would be fairly tricky. Unless it’s a common pigment, it would be very problematic.
I’m sure there are people who would have some success, but I think the outlay to manufacture these wouldn’t be worth it. Prop makers are only going to invest in production if they’re going to make money from it. I’m not sure there is the demand for a neck piece.
But back to the item in question and I think someone else said that if you have to split it open to get your head in, then you have to split it open.
Whether the split is in the rear or the side, if it’s abs or fibreglass it needs one.
If we’re saying that rubber must be used for that part, then rubber should be used for the whole kit.
Let’s not forget what we do and why we do it.
I and my garrison are sticklers for accuracy, but we’re talking about a 2” seam at the back or side of the neck, making a costume none clearable.
maybe level 1 - discreet join
level 2 - no join
level 3 - rubber
Anyways, to the guys doing the CRL and the guys who have put the hours in researching, thank you.