Q on Magnesium Oxide and P&B Shakes

I have two separate, but sort of linked questions.

1. I'm looking into the oxy-whatever route for bowel cleansing only because it seems to be a calmer way to cleanse the bowels. In reading about all the oxy-whatever cleanses, all have mag. oxide in them - so would it work to just take a mag oxide supplement? Or do these specific cleansers have more than just the mag oxide in them to help the cleanse?

2. Sounds like P&B shakes work great for a lot of people, and are a lot cheaper than the oxy-whatevers, but after reading a lot of posts on here, I'm scared to go that route! Even on the bottle it says that if you don't take enough water, then you could choke. I have a hard time taking larger pills anyway, and I'm scared that it will get stuck in my throat. Can anyone ease my fear? I WANT and NEED to do this cleanse, but have very little money to do anything right now.

If anyone can help me, I would greatly appreciate it!!
Marnie Tweet