Still too small??
If the GBR's are say 3'' each, the plec is, 4" say.
so that fit's the 1in/Gal rule, but then there's the shrimp...
It's a planted tank, and if you've got a fine filter, I'd say you're fine as you are...
But then again I hate to go against hc's word, I'm not nearly as experienced.
And also I am sort of guilty of the occasional overstock, never to my fish health's disadvantage though.
edit: not to mention pleco bio-loads tend to be higher then avg fish if i'm not mistaken. I'd certainly say you're pushing it.