good luck with getting into DYS! I hope good news is heading your way.
I don't have much to add since we are just starting go down the rapid learning path ourselves but I keep hearing the "don't accelerate too much, you don't want DD at a place where there is nothing left to teach" mantra at school.
I'm also seeing very rapid trajectory of growth in our DD. But like you, DH and I decided against advocating for a grade skipping even though this is what we originally thought was best for DD, simply because they would have to continue to subject accelerate anyway.

I have a question re: singapore math. Do you buy the text books for your DS or just the practice and challenge word problems? I purchased the textbook for DD last summer and I found I didn't need it. TIA.