Hi Doug
Sorry but you are mistaken. Later Taycols such as the Double Special had a separate reverse winding that provided a slower speed in reverse when selected. There are two connections one for forward and one for reverse. You can use a relay or double way switch to alter the contact.
A modern solution is to use a bridge rectifier as an electronic switch.
I have one and have done the conversion and it works.
Current is high and 25 amp capacity is recommended for the Double Special.
Please have a look at
http://taycol.tk/Rectifier.html
There is a diagram showing the separate coils and how to connect the rectifier.
A fuse is a must as you have advised and for reasons explained in the article.
I do agree your solution will work but I would suggest this alternative works using the Taycol as designed and avoids any disconnection of coils.
Whatever method is used the increased current will require the bridge rectifier to be mounted on a heat sink.
Hope this clarifies and helps you understand these fascinating motors in all their variations
Dave