need to add a sump

[freshwater]

I am thinking of adding a sump for my skimmer. I already have a refugium 20G which sits under the stand.
I have 2 choices.

1) get a 10G tank and sit it next to the refugium and get the overflow in the sump instead of the refugium and then use a pump to send the outflow from the sump to the refugium.

2) get a 10G tank and set it up so its higher then the refugium put the overflow output in the sump and then due to the gravity send the outflow from the sump to the refugium.

In both cases I will be putting the ES5-2 skimmer in the sump
9"x9".

Folks which of the above is better and safe choice and how I can DIY or buy it cheap/


Thanks.