I over line all of my salty six weights. I dont even think twice anymore. Never had a rod that had an issue fishing a 7 wt shooting head. I'd wager most modern 6 wt rods could handle an 8 wt line with little issue.
For the PS fishery in particular I see zero downsides to over lining but several benefits.
For the PS fishery in particular I see zero downsides to over lining but several benefits.