I solved my parippu vada problem. I soaked the lentils for 45 minutes-1 hour, drained thoroughly and then ground.This ensured the right consistency.

Also, I soaked thuvaram & kadala paruppu together with a handful of raw rice and the uzhunnu paruppu separately. Measurement used was 1 cup thuvaram+ 1/2 cup kadala + green chillies, dried red chillies, ginger, asofoetida, curry leaves and salt. Ground it in Sumeet mixie without much water, stopping regularly to mix the ground stuff in the bottom layer with the unground at the top. Drained the uzhunnu, and added it whole to the ground mixture and immediately made vadas. It turned out nice and porous and light and tasty.

Shoba