I can give you confirmation on how the sentry drone setups are doing vs. c5 sleepers. Garde's and Bouncer's own everything that isn't a frig pretty well and will own the frigs as they are burning in. When they get in under 20k or so you're going to need light drones to kill them. Cruisers under 5k seem tough for the garde's as well, but webs would help that. The more target painters and webs you can bring to the party the better off you'll be. If incursion rats are similar to c5 sleepers in health then you don't need to worry about wasting your dps. From what I've seen 75 sentry's only 1 shot cruisers when using gardes and the cruisers are near your optimal or when catching frigs burning in towards you near the garde's optimal.