SA GLX 5 or 6wt

I plan to replace my old cheapo line and reel I got when I purchased my
first rod, a Sage DS2 5wt 2 piece. When the DS2 rods got discontinued
and went on sale I got myself a backup\travel\nymph DS2 6wt 4 piece.

I am looking into one "general" dry line, preferably one I could use
with both rods.

I would be doing dry\nymph\swing fishing on smaller\medium and
occasionally big rivers.

I was thinking of buying a 6tw WF line but since I was considering a SA
GPX line I can't decide on the weight.

The DS2s are medium-fast and the GPX is supposed to be 1/2wt heavier
than "normal" so I am afraid a 6wt GPX would be a bit too much for the
5wt DS2.

A 5wt GPX (that is more of a 5.5wt) might be a bit to "light" for the
6wt DS2.

Any recommendations ?

Thank you

Zoran