Watch the (B) Adding Bass Notes online guitar lesson by Fareed Haque from Jazz Comping Survival Guide
One way to stay out of the way of the bass player when playing Freddie Green style is to keep a simple bass line. Ideally a line that stays on the low E string as much as possible will be fat but not too invasive. In order to stay on the low E play roots when root is on E string, but play 5th when root would fall on the A string. C7 for example with G in the bass will sound nice and full. The bassist will likely play a low C, and guitar will hold the 5th and then the 3rd and 7th creating a classic rich jazz voicing.