Thank you for the recommendation.
So what makes the line so important? Im not fully understanding this.
The line is the number one reason why an angler succeeds or fails casting.
Even a rod that is marked 500-600gr lines like your 7130 rod may not actually work well for you.
People make the huge mistake of buying a line without test casting based on what the line rating marked on the rod; then blame the rod for not performing to their expectations.
My instructor has found that each rod has a specific "sweet spot" line - even multiple rods that are the exact same will have a different sweet spot because of manufacturer differences, blank rotation, and the angler...
Lines vary with length, taper, angler casting ability; but also differs with the type of angling (dry, nymph, wet, swinging, salt water) & terminal lines (sink tip, float tip, poly leader, straight tippet)...
Case in point: I have a G Loomis PRO4X 5wt switch rod with a grain window of 320gr scandi and 350gr skagit.
The actual lines that work well for me are: 275gr OPST Commando, 330gr Airflo Rage, 360gr Airflo Scout, 380gr Gaelforce ESSS, and WF-6 single hand line for dries/surface.
That's a huge range to cast for a rod - it's all dependent on rod, caster ability and fishing styles.
Take a look at my rod's tremendous range of abilities:- Peter Charles will demonstrate a spey line as well as a single hander WF line on the same rod for different applications:
Go find a store that will be willing to let you test cast various lines for the type of fishing you want to do....