Either will suffice for bass. If you plan to throw big bugs and frogs you might want to go to the 8wt. I have rods from a 1wt to a 9wt, and because the heavier rods tear up my forearm after a few hours, I have a tendency to pick the lighter rods. I have and use a Tennis Elbow arm wrap with my 7 & 8 wts. I also use Weight Forward Floating fly lines and a straight piece of Fluorocarbon for a leader when fishing scuds and San Juan Worms. Flouro sinks well and being a floating line it is easier to lift the line off the water. Oddly though my biggest bass on a fly rod (6½ #) came on a 5wt while fishing for bluegills.
Here is what I use for a arm wrap:
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Let us know what you end up with.