have you considered taking the molding off the 10 gallon tank? it might save you that 1/4 inch you are looking for.
also consider the amount of flow back from power cutoff of system, you sump will need to handle that. I am a K.I.S.S. kind of a guy, so for me a drain section a skimmer section a pump section, if I need or want a refugium I would just link it to the sump from a 5 gallon bucket or pail or rubbermaid container.
Remember when our Dad's used tell us "use the right tool for the job, those ones that do 2 or more things at once aint no good" , well my Dad used to tell me that all the time, I try to remember that when ever I do things.
IGO for those not familiar "in Gerwin's opinion"

Im gonna make my own shortcuts page up of acronyms that should really count on my site
