First off, always feel free to PM me, or anyone for that matter, your questions are always welcome! That's why everyone is here....to help one another.
You are going to get 1000 opinions on this subject.
My opinion is: I would use the MH light through the 2nd week of flowering, along with your vegging nutes, as this is when your baby will grow the most.
(alot of growers omit the vegging nutes at this point, and you always see them asking for help, wondering why they have yellowing leaves now, the reason why is because they totally switched to flowering nutes)
After that I would change over to the HPS light.
I hope this helps you in your quest.
Peace