Hi Guys

Im in the process of buying everything for my 1st ever marine setup. Im a beginner in this hobby so I'm not an expert at all. I want the flow of the tank to be very good.

The dimensions of the main tank I'm looking to buy are:
41" Long x 18" Deep x 25" Tall.
64 US Gallon
53 UK Gallons
141 litres

The sump I'm looking to buy will be a diy sump and I'm thinking of the making it from a tank with the below dimensions.
36" Long x 16" Deep x 15" Tall.
32 US Gallon
27 UK Gallons
122 litres

First of all I'm not going to rush into setting it up. Im trying to make the system the best i can. The tank, sump and stand will all be custom made so the depth and height of the tank measurements can be adjusted if any of you think they should be?

Im planning on having a 4inch deep sand bed in the main display with 35kg of good quality live rock. The finished tank will be overstocked with corals and about 5 fish.

The sump will have a large skimmer and some live rock in the 1st section. In the 2nd section i want a large refugium with miracle mud. After the refugium i want the water to go through a sponge and bio balls. Then finally in the last section i want the heater and return sump pump.

I am ready to start making the main tank now and have a few questions.

I was going to do the tank with 12mm thick glass. Is this too thick or is it a case of the thicker the better?

The front panel will be Starfire glass. Has anyone ever had any problems using this glass? I've heard it scratches easy? :s

What would be the amount of water i should look to turn over per hour through the sump?

I was thinking of having 2 Drain pipes and 2 return pipes. Do you think this is a good idea? or is it too much?

What size should the bulkheads for the drain pipes and return pipes be?

Would really appreciate any advice or help you can give me as i don't know much on this subject.

Thanks in advance!