I been using gearbox oil on my Norton chains for over 40 years and I get very long life out of my heavy duty chains, I fill a cap off the oil container and use a small brush to apply to the chain while spinning the wheel slowly, a ltr of oil will last years and years, but every major service I will pull the chain off and soak it in kero overnight and give the chain a good clean and inspection, free up any tight spots then heat up a tin container of GB oil on the stove (do this when the wife is out) and throw the clean chain in when hot.
My last chain threw the retaining clip doing a quick take off at a set of lights, it had well over 40k miles on that chain and thought I replace it with a new chain from the Chainman, when it arrived I put the old chain beside it and to my surprise there was no stretch in the old chain so cut the new one to the same length as the old one.
I now install the retaining link to the inside of the chain and safety wire it, in 47 years it was the first retaining link I lost, but the first original chain I broke doing burn outs, young and silly I know, lost about 6 links and the chain shot off down the road at high speed lol.
Using GB oil as a lube will get a little flick on one side of the rim but a quick wipe makes the alloy rim shine, but just brushing enough on without over doing it gets very little flick, I also use GB oil for my dirt bike chain doing it the same way with a cap full of oil and a small brush, but as with playing in the dirt I do it every morning before a full days ride in the dirt before hitting the dirt, with the road bikes I do it when the rollers start to shine.
Ashley