I read that 1/3rd should go to the gas, 1/3rd to the crank case (through oil cap) and 1/3rd to the intake manifold... (not trying to disagree but I was interested in doing this as well and was browsing around)
And don't you need a friend/sucker to keep the RPM up around 2 while you're sucking it in through the vacuum line? The easiest vacuum line would be right off the brake booster, no?
That tube that'* silver would be the one, right? Except it wouldn't be silver it would be black rubber.
Another tip I read was that you should put the seafoam in the gas tank then fill the tank with about 7-9 gallons of gas to mix it up.