re-ring or rebuild?

the twinport in my oval has a taste for oil, about 1 litre per 100kms.... I have a nice black chrome rear bumper and oil splats on my legs when I walk behind it....
I dropped out the engine, took off the rebuilt heads, of which are super black with a nice really thick hard crusty black build up on the valves which is hard to chip off, and on one of the cylinders it is apparent that wet oil has been leaking/forced out between the mating face of head and cylinder.
Pistons have crusty black tops, otherwise look fine, cylinders are shiney and I can see honing marks where the piston doesn't travel so me thinks its been re-ringed in the past. The oil smells like petrol and there was no resistance turning the crank with the heads off, the pistons moved very freely. Is it time for new pistons and barrells or can I get away with a hone and oversize ring kit, have never done either, just wanna know what my options are..... thanks!

Yes i iwould be fitting new barrels n pistons as a set and having the head sealing surface skimmed and the lapping the barrels into the heads

also while your there having new valve guides fitted to the heads

this is after you have removed the valves and springs and cleaned in the ports back to bare metal so you can check for cracks in the ports otherwise you may also need new heads may be cheaper in the long run rather than skiming and fitting new guides as the valves may also be worn

Nuthing like a top over haul to stop engine oil usage and leaking