Yes i use OBS on my trout spey, 8 wt on a 4 wt spey/switch. If i was to use the OBS most of the time I would size up the line to at least a 9 wt to get a better load on the rod. And my 8 wt OBS is a tropical version so it is slicker and a little stiffer up here compared to the tropics. I think...