[CB-750] Best Seafoam Procedure?

I want to try using Seafoam in my 2002 Nighthawk 750 with 1600 miles. I bought 
it a couple of months ago with 1050 miles. It runs fine, but I'd like to run 
the Seafoam through to make sure the carbs are clean internally. My mileage has 
been all over the place – anywhere from 36 – 49 mpg. When emptying the 
crankcase breather tube, the liquid has a strong smell of gas. I also notice a 
slight gas smell when I check the oil, and see some black soot at the end of 
one of the exhaust pipes. I haven't checked the plugs yet. Once warmed up, it 
idles perfectly at 1000 rpm. 

Does it matter exactly how you do this? Should it be added just before filling 
up, when the tank is full or does it matter? My concern is that it get fully 
distributed throughout the gas. According to the instructions, I'm planning to 
put 1 oz per gallon. I'm hoping I don't have to bring it in for the carbs to be 
cleaned and I don't know if I'm ready to tackle that myself just yet. Any 
advice is appreciated.