With the first QOS rule, assign browser traffic to a class of service with 100% all the way around. With your second rule assign NNTP traffic to a class of service that has 100% inbound but 1% - 100% outbound.
Remember that it takes 3 to 5 seconds to slow down an existing stream. This can be annoying for web browsing if the lower priority traffic is saturating your inbound. It is better to keep NNTP ( or torrents ) limited to a maximum of 95% inbound. You will not notice the loss of 5% very much compared to how much better web browsing will be with the 5% reserved head start.