Hi,Christopher.  (my son's name, too!)  Thank you for adding me as a friend and I apologize for not responding sooner.  My life is incredibly busy, but this community sounds right up my alley!  ;) 

Well, I am familiar with the symbology of the merkaba and sacred geometry, but definitely no expert.  =)  The Merkaba has been called a vehicle for ascension, the hologram of love and the sacred pattern which gave birth to the whole universe.  Accessing this is like accessing the Akashic. (are you familiar with that?)

I'm not sure if you meditate on a regular basis or exactly what your goal IS .... I am guessing you're working on expanding consciousness.  I don't know about any particular SECRET meditation, but I did come across this, maybe it will help you:

http://www.wolfcreekarts.com/Merkaba_Meditation_Technique.htm

or...hehealingsphere.blogspot.com/2010/05/merkaba-chariot-of-light-part-4.html

maybe try this link...http://www.maureenstgermain.com/BeyondtheFlowerofLife.html

"Welcome! Many Blessings sent to you!"

http://twistedsage.com/Documents/The%20MerKaBa%20Meditation.pdf