Greentek Sensors has a new EEG cap which can be applied in about five minutes or less and removed in seconds.
A previous model of the Greentek Gelfree cap could be applied in about 30 minutes.
https://openbci.com/forum/index.php?p=/discussion/1663/greentek-gelfree-s-eeg-cap
The Greentek S3 has become a device for daily use, only 5 minutes to start it makes it suitable for this purpose. Another limit is the running time of 2 hours. Masters of meditation and yoga like His Holiness the Dalai Lama, Thich Nhat Hahn or Yogi Bhajan reported or recommended to meditate or to practice Yoga for 4 hours a day. In meditation retreats, Buddhist monks meditate between 6 – 8 hours a day. Therefore a longer running time with up to 24 hr or longer would be desirable. I think it should be possible to modify the Greentek S3 with a laboratory pump and water channels for this purpose.