Does this figure really need the white undercloth which bulks everything up? I'm planning to kitbash this figure for cheap and was wondering whther it really is neccessary.
It's really up to you dude. I prefer it cuz Jack was a chunky Joker. But honestly, I don't think he looks all that bad without it either. In fact, if I had doubles I might be inclined to display one without the fatsuit. Here is a pic of him at SDCC last year without the fatsuit.
I think someone did it without the fatsuit and instead of that he jammed some cotton under the shirt to fatten him up. You could try that
Hmm, are you sure your not thinking of stuffing cotton in the chest/neck area to get rid of the fatsuit line that you can see through the clothes? I know a lot of people including myself did that.