I hear you saying the gravity idea wouldn't work well, but let me ask this:
on my 6/1, if I did do some sort of gravity thing, I'd set it up like an IV bag, with a flexible tube going to a metal tube that snaked down into the air intake. Then, when the engine was up and running, I'd turn on the drip and then turn it off as I was shutting down.
The question is, would a drip/dribble that would come out of a gravity feed like that *work* ? Or is it necessary to have a *spray*?
Right now, I'm just dropping a teaspoon to tablespoon down the pipe every so often while hot and loaded... and that seems to work well enough.