I chose that character because he actually does wear an enormous mask that covers his entire head, so it seemed to lend itself well to my giant-head-making proclivities. As it turned out, I went a little crazy when I was sculpting him and I wound up with a head that was significantly larger than any of the others I'd made.
The rest of the costume required a lot of work as well, and the oversized nature of the head increased those demands. I had always intended to wear a padded suit of some kind, but with the Toyman head being so very large it became necessary to make myself a pretty big fat suit to balance it out - otherwise I would have looked like a stick figure.
Also, the character of Winslow Schott, the Toyman, has a costume that includes a light purple sweater-vest with red trim, and a red bowtie. Now, I leapt to the conlusion that I was not going to find a store that sold light purple sweater-vests with red trim that were large enough to fit over a homemade fat suit, so I taught myself to crochet and I made it myself.
The final touch was the bowtie. I cut a wedge-shaped ring out of couch-cushion-foam, and covered that with red felt. I sewed velcro to the front. Then I made a big puffy bowtie shape out of red felt and stuffed it like a pillow, then sewed velcro to that.
This way, I could put the wedge around my neck, padding my tender clavicles from the heavy Toyman mask, while the wedge shape helped to push up the rather topheavy mask so that the giant face didn't look like it was always looking at the floor.
And I just stuck the bowtie shape on with velcro. Problem solved!