[JBinUTAH]

I have a line question I would like to get some constructive opinions on.
I have two 5 weight fly rods, one Sage XP 9'-6" and one TFO TiCr-X 9'. Both have a large arbor Orvis Battenkill III. I have Scientific Anglers Mastery XXD WF-5-F on one spool and need to put line on the other for the second rod. I already have a new box of XXD but in WF-6-F. I have read about sometimes using a larger size line than the rod is rated for with mixed opinions. I have also thought of going with the SA GPX WF-5-F. I am a novice fly caster at best, but improving. I like the XXD, but have not experienced others except the GPX. I have a third spool with Cortland 444 Clear Camo for a sinking line I could use on either rod. I fish the Provo, Henry's Fork, and Madison, etc.

Should I install the XXD 6wt.? Buy GPX 5wt.? Buy??
Tell me what you think or may have experienced. Thanks in advance for the help.