Hi any help please.

I am refurbishing an old Diawa Whisker 7/9 11ft 3 inch 3 piece, I want to put a full double handle on the rod, replace all the guides. to use the rod for fishing small spate rivers for summer Grilse.
I am interested in the Scandi Short Versitip setup as a line for the rod.

But which line, all very confusing.

Can anyone give me some advice, as these lines are very expensive just cant afford to buy twice ?