Spot feeding isn't really needed but some polyps grow faster and show improved health with spot feeding, stick with micro foods like tlf goniopower, reef roids, etc. but don't over feed as your nutrient levels like nitreates and phosphates may go higher then expected if your mechanical and biological filtration isn't up to par.
Dosing, well you should only dose what your tank demands so only dose what you can test through visual coral/fish changes or ideally through standard hobby test kits. The key is to go slow and look and see how your livestock reacts. Also, most elements can be replenished with regular water changes, it really depends on the demand from whatever is growing in your tank. My tank is mixed reef and dose a lot of chemicals, Red Sea coral colors A 1.5ml/day, B .12ml/day, C .30ml/day, D .20ml/day, Strontium mix 30ml/day, DIY 2part (values are estimates as I have an autodoser and can't remember the exact values atm lol) Alk 130ml/day, Cal 90ml/day, Mg mix 40ml/day.