Oil, I'd use one or two coats in fairly quick time, wiping off between. Then daily for as long as it took to build the finish I wanted. It can be applied with rag, cloth, synthetic abrasive, wire wool or even abrasive. Sanding (use your final grit again) will build a slurry and fill any grain or small cracks.
Poly, I've never used but definitely follow the instructions on the tin, the manufacturer knows best. The only warning I'd offer is it set's more slowly in the cold, so be prepared to adjust the drying time upwards.
Now the hard one, a 50/50 mix, I don't think I'd try to use any abrasive with it. So work it like the straight poly, but that's a best guess. Anyone else done this and can offer a better answer?