I could imagine the vibration passing onto the other saddles (and then the strings) instead of to the bridgeplate. So i would say hypothetically it would be better to have them seperated. But I'm not expert at this.
i dont think it will make much difference. callaham saddles are made not to touch. glendale saddles are purposely made to touch. I think i like them better touching because the saddles wont move when you do string bends.
off the top of my head i think the saddles touching are theoretically supposed to give you more coupling and sustain. the theory behind them not touching is to get rid of unwanted harmonics. i use the glendales myself, but i'm sure i wouldn't be able to hear the difference between touching or non-touching saddles.
It really only matters if there's a rattle when they touch. Then you can either jam 'em together tighter or pull them apart. Sometimes you get nice sympathetic vibrations from the other strings when they touch, sometimes ugly sounds similar to the "wolf tones" you get when the pickups are too high.
The issue is much more important with a Jaguar/Jazzmaster bridge, for all the same reasons. Every guitar and every set of strings reacts differently, so there's no set rule.
I like the "apart" kind because they are easier to manipulate and can be used in a wider variety of applications. If there's a tonal difference I'll be darned if I can quantify it. And I feel most confident that a large factor in why the 6 "hammer" barrel saddles on the MIM Deluxe Nashvilles and Standard James Burton Teles have issues is that crowding leads to saddles pushing other saddles out of position and uneven amounts of down pressure on each of the saddle height screws.
Some G&L ASATs (the specials and z-3s, I think?) have those (link removed)that have a screw on the side, so tightening it pushes the saddles together, and they resonate with the bridge as one mass.
Might be an apples-to-oranges comparison on account of the design, but I hear great things about that bridge on G&Ls. I can only assume you would be getting part way there by keeping your saddles snug on a more "traditional" tele bridge!