Those are silicon. They don't absorb the milk. The milk has to do somewhere, so my guess would be that it would run down and get you wet someplace lower down. I wouldn't get those. You want something that's absorbant and comfortable. Something that's maybe the consistency of cloth diaper cotton or maybe fleece. It has to be absorbent, which cotton would be. They should be washable. Don't get square or rectangular pads. They crinkle inside the bra and the wrinkles are very noticeable through a shirt. They're very uncomfortable. Don't get flat pads with a slit in them. The milk will leak. You want pads that are round, one piece without slits, and fit inside the bra well. Your best place to get these would be a place that specializes in baby stuff, like Toys R Us (Babies R Us). I would recommend going to a maternity shop. They carry items like the pads and nursing bras. Nursing bras that you can open with one hand are ideal.
I think something like this would be more efficient and comfortable for you.