I do a mix of Pranayama 2 + the Pranayama described in Gamana's book.
You can play around with different versions, the essence is the same. I like to visualize energy flowing up the spine to the very top of the head through all the charkas. I think the more precise your visualization gets, the better.
Gamana says not to visualize the energy flowing up each chakra, but I feel it's more powerful to visualize it. I find that doing a detailed visualization also helps stabilize and focus the monkey mind.
Experiment around and see what works best for you.