Have you worked with neckties before? If not, you may be in for some challenges. I believe that most of the quilts that use large blades for a Dresden plate are using the entire tie. If you take the tie apart in order to use the silk as a single layer, you need to use a fusible to give it some substance.
I took some silk ties apart and hand washed them prior to fusing, and I had such a mess I gave up. These were old silk ties and the reds bled like crazy.
There's no problem with making your own templates. I would cut the Dresden spokes out of freezer paper, then iron the freezer paper templates to the wrong side of the silk, leaving them in while piecing on the machine. This makes matching the edges for piecing easier.
Be sure to Google Dresden tie quilts before starting so you have an idea of some of the issues that can arise working with ties.