Brakes

[mark]

Im new to making brake lines so any advice will be greatly welcomed

Ive done a few running repairs making the odd brake line over the years on daily drivers but just dusted off my flaring kit and read the instructions. It illustrated a female flare, a male single flare and a male double flare, when and why do you use different types of male flare?

Also my hydraulic brake light switch from a vw caddy seems to be flat on the end of the male thread, what kind of fitting do i use when i install this switch. I assumed it would just fit in the t piece.

I probably know enough to have got my way through this job but i thought i would ask on here as people who have lots of experience will probably make lots of usefull suggestions and make my life alot simpler this wk end when i start on them