The blades are similar enough to say they are essentially the same. The difference is mainly the scales. They all shave the same. 6/8 hollows.I would say I like the 208s. But only because of the look. Ive shaved with all of them.
Most are 6/8 or a bit less. Some models have a double stabilizer and some just the shoulder. The #66 has basically zero finishing. The scales are different.
If you want to just hone and shave, try anything #200 or higher. If you want to have a half finished blank for you to turn into your dream razor, go with a #66.