I would like to suggest also, the the response recesses may not be too shallow for flowable. I have successfully siliconed a YYF Mighty Flea without the response falling out after a lot of play. Try this:
After the old response is completely removed, use a cotton tip and some methylated spirits to clean the recess thoroughly (not sure if it's called that in the US, but it's basically alcohol).
Then let it air dry.
Afterwards, apply your flowable silicone, being very careful to not allow it to dome up above the edge of the response recess.
Let it cure for 24h.
This should work very well for you.