If you had a pair you could do a PP with another dual triode.
As it is you might think about using that tube as the driver-output of a low-powered SE amp with maybe an EF86 voltage amplifier stage (or a dual triode in front instead for a gainy style low powered SE lead guitar amp)
As to its tube characteristics? You'll need to find a chart. There is a circuit for an EF86 with an ECL86 (similar sort of thing) here, which you could use as guide, and being careful to set the voltages of your 5CG8 appropriately.
Or use it as an all-in-one reverb driver and recovery tube?