This is probably rhetorical but is it stupid to only have one overflow on a 125g? I am thinking about buying one but dont want to spend the extra money and time creating two.
Aqueon offers their 125g with dual overflows so you don't have to do a diy overflow but to answer your question it is not stupid to have one overflow. It really comes down to what you decide you like.
The dual return pumps will be irrelevant in this topic i'm trying to decide if I should use a dual overflow to increase the mechanical waste in my sump or to use one.