Celibacy/Abstinence/Tonsuring the head
I have read an article on 'Why many people who practice meditation shave their head?'. It was written that when we cut our hair, our body energy flow towards our head in large amount to restore hair which were lost. So, that extra energy helps in meditation.
And this is the reason why they shave their head on shivratri, a night before amavasya when full moon's energy and body energy coz of shaved head can be utilized for meditation.
But You suggest to have long hair?
The body (and therefore hair) are impermanent coverings around one's Atman (self), which will one day ripen & fade away. Those instances, where people shave their hair on a holy day or some time during the year is only a symbolic representation of letting go of one's attachment to this body (Asat) which one is not. Man is attached to his looks and body appearance, through Avidya (ignorance), and as a result takes great care to maintain the body and its parts attractive, through 'Dehatma Buddhi' (erroneous assumption that he is the body). This attachment is a hindrance to realization of the self, for attachment to the unreal always ends in suffering.
Donating hair to the family diety or at a holy place such as a temple (by tonsuring the head) is also performed for the very same reason. God has no use from receiving a devotee's hair, nor does he bless someone just because that person shaves his head & offers hair at the holy place. The activity is only an opportunity for the common man, who is engrossed with the unreal things, to develop some 'Vairagya' (dispassion), by aligning his mind towards God and letting go of something which he is attached to (hair).
The Buddhists also shaved their head for this reason alone (to develop detachment) and not any other. There is no benefit in terms of energy, through shaving hair. Shaving hair does not improve meditation by any extent. Meditation is achieved through merging the mind into the self, further to displacing past Samskara-s and Vasana-s and not by other means.
ॐ तत् सत्
(That Supreme being is the absolute truth)