Let me see if I have the math correct.....
7oz Dex/gal = 196gms
Us gallon = 3.8 litres
16oz US bottle = 473ml
So if you say for arguments sake you'll get 8 X 16oz bottles/ gallon
196(Dex)÷8(bottles)=24.5 grms Dex per bottle.
That's insane, I hope you meant 7oz/5gal, brewersfriend couldn't even...