building a 150G, glass edge and drill??

[phish]

Hi All,
I found this msg board about 2 months ago when I decided to build a saltwater aquarium.
Since then, I've been reading and reading, and reading.... you get the point.
There are 2 issues that I have not been able to make a decision on, so I figured I ask the experts.
1) What is better, bottom or back drilled for the sump, and is back drilled, how far up from the bottom?
2) the guy at the glass shop said that I may want to bull nose the edges so that there is more surface contact for the sillicone. I noticed all tanks have flat edges. What is better bull nosed (rounded) or flat?
Thanks in advance for your advise.

 

[surfnturf]

1)A matter of preference and space, a side mount would take up less space, bottom mount more space, each has it's merits and drawbacks.
2)If you use good bulkhead fittings, this shouldn't be a factor.