Is it best to feather your front brake only, rear brake only, or both brakes when cornering?

Is it best to use your front brake only, rear brake only, or both brakes when riding on wet or bad roads?

Is it safe to descend and corner on the hoods when riding below 30 kilometers (18 miles) an hour? I can descend and corner on both the hoods and the drops and even the tops at any speed but it feels most comfortable when going below 30 kilometers while descending and cornering to be on the hoods.

I'm new to the open road after being an avid track cyclist for over a year. My track bike had foot brakes so that explains all of my braking questions.

I've read many articles and watched many videos that say to do different things about braking techniques. I'm hoping to ask some experienced experts out there for safe braking techniques and the outcomes of what happens when you use certain brake combinations under certain conditions. I'd rather not experience for myself because I don't want to get seriously hurt early.