Maharishi stated on the Maharishi Channel before his Mahasamadhi that ideally
individual mantras should be chosen on the basis on the individuals Ishtadevata
as revealed by their Jyotish chart, it was not possible to institute this
during his time on earth but its a direction for future generations. He gave
the mantras forms for facilitating transcending. The mechanics of his
techniques and mantras cannot be discussed in a public forum without ruining
the innocent spontaneity and simplicity of individual's practice.
He also stated that each individual's caste should in fact be determined by
their individual Jyotish chart and that record is currently being played on the
Maharishi Channel 3 this week.
http://maharishichannel.in/CHANNEL_3/index.html