I added homemade leather toe guards to my skates too. But, I didn't sew anything. I took a rectangle piece of leather and I simply cut one large hole for toe stop bolt-hole and 4 to 6 little holes to put my laces through. No sewing!
[Check picture on profile, b/c this is my first post and I'm not allowed to post.)
You can kinda see where I put the laces through the leather. It's under all the duct-tape.
If you're wondering about the brand of skates.... The boot and plates are 18 years old, but Labeda skates do make derby skates these days. I've been doing derby for about a year, but I was a rink rat when I was younger.