On publics I see wayyy too many people gorging then trying to use web like spit, paying no attention to the fact that the amount of web is limited by area, you can often end up with 4-5 inch-long webs taking up virtually no space along a floor or wall when that happens. Which will make any of your teammates who know how to web *angry*
Zig Zag your webs, make some of them obvious to deter marines and hide others. (By webbing floors, low across steps, or along the break in a texture) web corners, jetpack flightpaths and parties of marines. If the marines have all left their spawn set up lots of long diagonal webs all over the place before laying into their CC.
When I go Battle Gorge, I'll web near a marine's feet, then web a point behind him, voila, instant webbed marine. Web back near his feet again, and you've hit him with two webs. If you're a camping ho-bag, you can set the first shot up beforehand and only fire off the second and third to spring the trap when the unsuspecting marine comes along, that leaves you with plenty of time to do lots of damage with spit.
A good delaying / ambush tactic in a map with lots of corners is to create a bottleneck for the marines by spamming 3-4 threads of web across an area that you *know* they'll want to be coming through. The left hand hive entry in co_ulysses is one place like that, web the top of the steps, then a point across the corridoor looking out, and any 'rines are gonna get their heads webbed.

This is only really fun if your team are supporting you though, because then they can attack from 2-3 directions at once taking the marines by storm, if you've got no backup then keeping them at bay's about all you can do.
On most public servers a smart gorge can keep 4-5 marines at bay for 30 seconds or so easily - as so many are unwilling to walk into web.
A decent battle gorge *can* take down a full power jetpack marine with resupply, it just doesn't happen all that often.