this should help with a little info for glass thickness and tank dimensions.
http://www.aquariums.ltd.uk/Technical.asp
hope your new business takes off, love the double stand in your portfolio.
a little warning on this " If you do not like a piece we will re-do it at no cost to you until it is to your liking". this could get expensive if you get a very difficult customer who likes to make trouble in places just for the sake of making trouble.
maybe some re-wording to cover your back rather than a blanket "if you dont like we will re-do for free" statement. maybe send them a sketch of what you intend to make first and if they agree then they cannot ask for it changed for free, small changes can be made after agreement but at extra cost as the original design was agreed upon. a get out clause for you if you will, to cover yourselves from bad customers.
of course this is just my thoughts that you are leaving yourselves wide open and you are a business afterall, not a charity. I know you want to stand out from the rest but that statement has the potential to bankrupt your business before its had a chance to flurish. small print and T&C's are the key.