Your post is ages old, but I just joined and saw it with no response, so I thought i'd reply.
Hoodia is safe and a good idea for your purposes. But stick to good brands - flora, source naturals, paradise herbs. Also, bija tea has hoodia tea.
It tricks your brain into thinking you're full. Drink lots of water (it thinks you're not thirsty, too), and take it half hour before a meal.