Hi,
This is a very useful question. The effects of Varuni naadi is exactly as described by you. In olden days, there were yoga practices called "kriya". These were done to control the nadis through external forces. Once used to external, we would be able to control from inside.
These kriyas are to be very effective in internal cleaning and control. But now a days its very difficult to find people doing these kriyas.
Thanks,
Ram
ललिता एव इदं सर्वं