I agree with Chris in regards to the cast weights on either the GTK74PG or Zenaq FC76-4. While they both fish PE4-6, their ideal cast weights are in the 60-120g range. In the Zenaq range, the FC83-5 could be the ideal choice as it is designed to cast weights in the 90-130g range comfortably and fish PE5-7. It is light in weight and utilizes the very fast recovery graphite which is typical of most Zenaq rods, making for a very responsive lightweight GT Stick.
In the Smith range there is a bit of a gap between the GTK74 and the next rod up, the WRC80P. While the 80P is rated as a PE6 rod, I have known many anglers to fish PE8 over it (with care). I feel it fits more into the mold of a heavier class rod in terms of its feel and balance, when compared to the Zenaq FC83-5.
Regards
Duncan