If the batter is too thick the idlis will be tough, if its too watery they will not fluff up. So get the consistency right. Thick pouring consistency.
Can freeze the batter to make more idlis, dosas, uttapas, white dokhras.
Adjust spices and salt according to your taste.
Some sambars have a bit of gur some don't. Its your choice. I prefer a bit of gur.
If your family loves idlis, its best to invest in an idli maker.
If you do not have an idli stand, put the batter in small steel bowls or silicon muffin cups and steam. Remember to grease them.
If the sambar becomes too thick, just add a bit of water.
I have added mint in the chutney as most restaurants in Bangalore make the chutney with it. If you want, you can use only coriander.