Planning a 75g?

I recently completed a 90g stand for my 55g. I wanted to encorperate a sump fuge, so I picked up a 90g stand for $50. I braced it with 2x4's and put a plywood top on it. I then painted it all black. Now I have a 90g stand with a 20g long sump fuge so, why not upgrade to a 75g.

I want to do this as cheap as possible. I am searching craigs list for a cheap tank thats in good shape. I am thinking of visiting glass holes to get an overflow kit. Any one have any expierence with them?
700 gph Overflow complete kit - Glass-Holes.com dope aquarium stuff
Would this be ok for a 75g? I like this kit cause I could still use my mag 5 and not have to spend $100 or more on a new pump. How easy is drilling a tank?

Also I am debating or going with a bare bottom or a very shallow substrate. What are the benefits of going bare bottom?

Lastly. I am currently running a Nova extreme 4x54watt T5 fixture. Would this be enough light for a 75g?

 

drilling a tank is easy but you have to be careful and do it right there are good videos on you tube with step by step instructions,!DONT DRILL TO CLOSE TO THE SIDES!,getting the drill can be pricey though and they are only good for a few holes,i use the dreml with a diamond tip method if you don't have onealready the dreml is something every diy'er should have, wonderful tool,, about the bare bottomi would not recommend it unless the display was going to be bare bottom and you were going to have a bunch os substrate in the sump, the obvious advantage to bare bottom displays is it's easy to clean but there is a reason the berlin style fell out of favor and that reason is bacteria,you've gotta have someplace for it to grow and all the liverock you could stuff into a 75 gallon won't even come close to the surface are provided by a 50 lbs bag of aragonite or crushed coral, i use that fixture on my 75 and while some would say its underpowered i have great success with it running one actinic one 75/25 and 2 10k's,throw the bulbs out that come with the fixture immediately though, they are garbage. i'm not familiar with the overflow company but i'd go for it i.m.o an overflow is an overflow, as long as it works its great.
hope this was helpful

 

Thanks for the input!