I ride on patched tubes all the time. Never had a problem until I get another puncture. Then I just patch it again. So I think you will be fine patching old tubes and using as spares.
I mostly use the Touring patch kit, where the patches already have adhesive, but there is also a tube of glue that you use first.
2011 Jamis Quest "Cy"
2009 Trek 7500 "Diesel"
2008 Rans Stratus LE recumbent "The 'Bentley"