trying to design my 1st sump

I guess its going to be obvious after you read my thread that im new at this. I'm currently in the process of constructing my sump. Its a 20g long (30x12x12) sump for a 65gal tank. The 65gal tank will be mainly for coral and the most 5 fish . Ive purchased an Octopus Super Reef 2000 protein skimmer and a Eheim 1262 return pump to be placed into the sump.
Please reply with design options. My goal is to get it right the 1st time. I read in another thread that the Octopus super reef 2000 needs a 12X12 space with 6'' water depth for proper performance.

 

I would use the skimmer in the side the water flows in at/macro algae and sand in the other side with a small section for your return. You should have enough room to fit everything in.

 

i read somewhere that a refugium filled with algea isnt quite effective unless its 3 times the size of the fish tank. Hence a 65g tank needs a 195g algea filled refugium to be truly effective. Is this true?

 

not sure where you heard that, my 10 gallon fuge on my 90gallon display tank is extremely effective.
here is an efficient design that many of us use.

 

http://www.3reef.com/forums/reef-aquarium-articles-how-tos/all-about-sumps-filters-fuges-79852.html

This should tell you everything you want to know about fuges and sumps.

 

This may help. your skimmer may need a platform to raise it to the proper water level to ensure correct operation. here is a drawing with recommended hight and width settings.