The inch rule does not apply well to marine systems. Remember, only SMALL amounts of nitrates can harm your nano system. Although the fish are small, you have to FEED THEM. Gobies often need frequent feedings. This will raise your nitrates on top of the nitrates converted over from ammonia that the fish secrete. I cannot overemphasize this.
FW rule bending does not work well in nano systems. Although I sympathize with your desire to have many beautiful fish in your tank, this is the restriction of keeping such a small marine tank. If you push these limits, the results are the following:
"Help, my corals are closed"
or
" My fish disappeared, can someone help"
Think twice and remember the nano tank warning, "Beauty happens slowly; disaster comes quickly". SH