Newbie Duelist Ranged Build - HELP ME

I'm relatively new to POE, especially with ranged builds. I'd like to develop a ranged Duelist Slayer build with Chaos damage, life leech, evasion + armor bonuses, fast attack speed and fast movement.

Here's the current skill tree plan

https://poeplanner.com/ABAAAQ0AEBQAAIObLV85ivDEgrCr9Obd476ndcvqYs2YjX63tkMxv9VTu0SeIWBAoHrvBS107Ua3029eE-9Ok6hzaxEaV1SKsxm0LYMVILUIsTAlP3Ghj0_dDVuvFHWkwuXmnMS3IhjbOSUz2el2LGSqpHfXVvrYYNctSQ-q-Kiiwdg6sw2Nh3ZKfWeg45_8xYAiZKY_bHjrCpvnCu960350rgBeGY7tgwguLOkA7oazKk0_J0rIbqq18nJsbEYyCXgNwBpvOzWS_o9N46ZXOuHyRf4K2L0xnn1brEdFluss4oBMMmVNvTZHfk4qKjgj028nj2CaaulGcsOrC8wGkAqlNfVhO7YMcLKAhrSFpyefAAAAAAA=

I'm unsure about which attack is best for chaos damage single target, and which is best for groups. I'm using Caustic Arrow with chaos damage and multishot support atm. It works pretty well at low levels, but does it scale well at higher levels?

Should I switch to Toxic Rain or Scourge Arrow? Should I have a main bow for clearing groups, and a second bow for bosses?

I'm noticing that mana management is an issue even in the early game. should I invest several skill points into mana? If so, what should I cut from the build to add mana? Or should I invest in some gear that provides mana bonuses? perhaps mana on hit or mana on kill?

I'd like specific suggestions about my build, leveling and end game gear, and chaos ranged attacks. Please don't just refer me to existing builds, as I'm unlikely to fully grasp a lot of it - don't forget I'm still somewhat a noob, and this is my first attempt at a duelist ranged build. I'd really like to develop this build as much as I can. I tend to learn better from my own mistakes rather than only following existing guides.

Many thanks!