feel for English sound sequences

credit: Evelyn Gonzalez

I asked my students (with 7 to 9 years of EFL at a German secondary school) where in the phrase wet blanket they would expect assimilation to occur. The overwhelming majority correctly spotted the word boundary. Additionally I made them guess what kind of change was likely to take place. To my disappointment many of them opted for /wed blæŋkɪt/. Definitely not a native speaker's first choice, is it?
Next they had to classify the change from /wet blæŋkɪt/ to /wep blæŋkɪt/ according to the criteria I had introduced before:

1. direction
2. extent
3. distance
4. parameter
5. obligatoriness

Congratulations to those who came up with this answer:
Optional total regressive contact assimilation of place of articulation.