First I remove all the rust using a wire wheel on a hand drill (several different sizes and shapes).
That takes about 2-3 hrs per piece. I make it all shiny clean metal in every nook and cranny. Then blow and wipe all the dust off using a dry cloth.
Then I wipe it down with veg oil so it doesn't flash rust.
I then wash it with soap and water to take off the oil and give it a scrub with steel wool before quickly drying it and putting it on a lit stove burner to give it a fast heat to drive off any water so as to not let it rust again.
Then I wipe it all again liberally with veg oil to wait for for the seasoning process.
When it time to season it, I wipe it with paper towels so only a very light coating of oil remains before putting it in the oven at 450 for an hour. Let it cool in the oven before repeating oil and heat cycle. I do that for a total of 5 cycles.
Light oil layers are key so that the oil polymerizes properly and you build multiple thin layers so that it becomes completely non-stick.
The rule of thumb is that if you think you might have too much oil on the surface, then you do. No such thing as too thin a layer, but too thick will make it sticky and gooey destroying the fine seasoning you are after. Better to do more thin layers until you are satisfied. One layer too thick will ruin it.
The end product is a fully seasoned pan ready for use. Just be sure to lightly oil all interior surfaces before cooking to keep stuff from sticking to the sides.
With cast iron, cooking with oil is your friend for long lasting performance.