height of toothless overflow box

[scumonkey]

Ok...I'm 'bout ready to install a DIY overflow box inside my112 DIY tank!
I'm using 1/4" plexi and DO NOT want to cut teeth in the top.
I want to adhear gutterguard to keep kritters out and allow for maximum flow across the open flat top.
How close to the top of the tank should the overflow box come...
1 inch - 2?
I went to the LFS and looked at a megaflow tank. The overflow box came right up to the top of the tank. The open slots appeared to be about 1 1/2 inches tall with a 1/4" solid rim above them. If I were to cut the sloted part with rim off, that would make the overflow box come up to about 1 3/4" from the top of the tank. Does this sound right? Should mine be closer to the top seeing as there will be no flow restiction due to the lack of slots?
All advice will be happily digested!!!!

 

[BeanAnimal]

How wide is the overflow and how much will you be pushing over it?

 

[scumonkey]

The overflow is 14 inches total and there is a 1 inch bulkhead = aprox 5-600 gal an hour. the tank is 30 inches tall.

 

[scumonkey]

Anbody have any thoughts 'bout this? I'd hate to do everything right- only to mess up with this inexpensive but VERY important component!!

 

[BeanAnimal]

Give yourself a 1/2 or so. If you could build a longer overlfow it would be even better for surface skimming and create an even shallower lip of water.

 

[scumonkey]

Thank YOU BeanAnimal!!!!