Welcome to the site!
From past experience I think the majority of the people on here who have tried DA have liked it. Me being 1 of them (DA for IBS was great!). I think it was Canyon who mentioned taking the DA for Gas and liked it. I got a free sample and after it ran out I didn't keep up with it. I do intend to, eventually.
Along with the ginger root tea, mint and fennel tea work well too for gas. At least, they do for me.
As far as preventing the gas... you need to watch what you eat and how you eat. Chew your food thoroughly, do not talk too much while eating, don't use a straw while drinking, and stay away from gassy foods. Beans and raw veggies especially. Too much sugar can cause gas too.