LOL - lot of questions that you will find hard to have answered this early.
Are you looking for the cheapest or best quality PSU to run them? 120V or 220V?
Overclocking depends on how cool you can keep the unit.
Does your basement have cool air coming in and a way for hot air to leave?
There are 2 basements im deciding between im almost sure that both run on 20 amp breakers,
I will have to install some sort of ventilation for the heat. both basements have Central air.
As far as PSU, I don't know what I should get the recomended is APW 3 which is 176v -264v.
I don't mind spending more on something that is worth it or less on something that is cheaper, so i guess im asking what are the good options for PSU for these miners.
Honestly the ventilation and heat issue really depend on how many units you are looking to run. A basement with one miner and has central ac is fine. Running 40 of these down there....issue. i would stick with the bitmain psu to pair with the L3s. If you are looking to coin switch based on profit there are multipools to do it for you i would stick to one of the better ones.