Could you fit a 1/4" JG fitting to the end of your 1/4" barb you are inserting into the rubber grommet? Basically the same fitting you would use on youre keg disconnect.
If this works you would be eliminating the elbow, post and disconnect.
Yeah, I imagine you can get the right JG part to go on the barb. The threaded side of the barb is just that, a standard threaded fitting. But then you can't disconnect anything until it's empty, unless you also put some kind of stopcock in-line.