Welcome to the Do-It boards Striperman.
The Do-It Ultra Minnow Blade uses a similar blade blade blank, but the cast on lead portion resembles the Shad Blade bait, also from Do-It. If you take a look at the on-line store and check those two baits you'll see what I refer to. I'll get a picture and a measurement of the blade blank used that is much like that of the Ledgehog baits in your link.
The overall length of this insert is 3.25". I know the overall length of the finished Ultra Minnow Blade bait is close to 4". Hope this helps.