30, 35 and 40 wt shock oil will be fine for off road in your GT. You don't want anything heavier unless you plan on running on road with it. The AE shock rebuild kit should have everything you need to rebuild your shocks. If you plan to use your Evader shocks, Check the rear droop length before running them. I think they are longer and will cause the axles to rub the arms close to the rear carriers and you could bend or break the axles. If so, you will have to put a spacer on the shaft inside of the shock to limit travel.