I went on a search for those wheels and they are essentially extinct. I purchased a lot of prewar wheels from "under the table" and was able to make a set up for my use.
The 1935 Parts list shows the 1700E using the 1661 wheels. In 1937, the parts list shows the 1661 wheels for early production and 1700E wheels for 1937 production units. The 1942 parts list shows use of 1664 wheels. I'll have to do some digging to see if the actual axles varied throughout, specifically in diameter and if the gearing changed.
Post pictures of what you have and we can try to match up with some of the parts listed above. Look at spoke count, the eccentric crank pin/mount (if any), the gear teeth count and diameter.
