It would depend, fishing for bass somewhere in New York 10lb line is all you need as bass will only get 5-7 pound. But if you're fishing in the west or south like California or Texas where it's not uncommon to catch bass exceeding 10lbs you'd probably want at least 20lb line so they don't break you off in the cover.
You'd probably want to go with 10lb-15lb line on the 6.2-1 reel because you can reel much faster and get the fish in before it reaches weeds or cover. I personally wouldn't use line over 15lbs, but the 25lb line would be better suited for the 5-1-1 reel where you can fight the fish with a slower reel.
