4 Site RDWC Build help

So I’ve see numerous builds, understand what i’ve got to do generally.
I currently have a 4&6 set up which I bought.

But I want to add another 4 set up and build it myself .

I would like to have the buckets in a straight line.

Main questions are.

What size lines to get that will be moving the water from control to buckets.

How I go about drilling the holes in the buckets and water sealing them? What sort of drill bit do i need?

Otherwise I know what i’ll do for my airstones, water pump in the main rez.

Miss anything?

Hey, by no means is this coming from a professional, but I’ve done a fair amount of research into building my RDWC 8 bucket to controller/reservoir set up.
To answer your first question, using a drill and drill bits known as “hole saws”, you can cut a perfect circle into your buckets. You can find them at your local hardware, however, amazon sells different sets that meet every DIY DWC hole requirement. My set for 18 dollars included sizes up to 5 inches and saved me a ton compared to Home Depot. BUT you must also invest in a $10 deburring tool. It will smooth out the edges that the hole saw created. This is very important to having an airtight seal. Also I’ve heard of some people drilling the hole in reverse to keep it as smooth as possible If you’re asking more specifically exactly HOW to do it, then you’re going to want to use a sharpie that shows up on your buckets and mark a line on exactly where you want you holes to be. (Much better descriptions available on YouTube) but remember to factor in the expected water level and also the curvature of the bucket. Drilling too low towards the bottom of the bucket will cause leakages. You should strive for the bottom of the drilled hole to be placed about an inch or so above the bottom of the bucket, just to be safe. Now if you’re trying for an watertight seal and cut the right size hole and use the deburring tool to smooth out the edges, then you should be completely fine. If not, aquarium silicone can remedy that. I can’t speak on bulkheads because I use 2” uniseals for my line from the buckets to the res. Neat work and correct measurements are 95% of the work, I assure you.
Good luck on the plans. Let us know of your success!