I do 6g/2L for heavy feeders, and 5g/2L for lighter feeders, but I've been boosting that 5 to 5.5 lately and like the results so far.
It's very much a cheat of sorts... you're probably feeding them too much to begin with but not enough to end with. I try to address that with a lighter nute load at the top where young roots are developing. When I get my game nailed down I might start supplementing some with a touch of liquid nutes late in their lives.... we'll see.
The shape of the soda bottle 2Ls play into the equation some as well. They give a good size to allow for a good flow of water and nutrients up the medium column as the water at the top evaporates off.
Another thing to remember.... heat effects nutrient levels, so you might be able to adjust their nute levels some using garden placement and temps. I keep my youngins next to the AC inlet... that keeps them a touch cooler thus a bit lighter in the nute department.
I'll increase the Osmo volume a tad. My apartment stays at around 73 year round. I'll keep the temps in mind when things start to heat up, because the tents tend to get crazy in the summer. Thanks for the heads up.