The 8-man GH pack is your money unit. Very tough to move off of an objective, especially when covered by a LF pack or two and/or supported by an Independent Character, but it isn't invulnerable! The trick is going to be to get them where you want them before their Rhino is toasted and to prioritize your firepower against units that can harm the Hunters, so we're talking units with Power Weapons, Plasma guns, ML and LC...stuff like that. Flatten them with everything you got ASAP, or at least threaten them enough to restrict their deployment or keep them on the move and not shooting at you.
In Objective claiming games just squat on one and you've got it. Use the smaller packs to disrupt your enemies plans. Unless it comes down to KPs, the 6man units with Razorbacks are very shooty for such a small unit and can face down a slightly larger grunt unit or a single MC just fine (well, once per game that is). Also good for speeding into the enemy's backfield, ignoring the guys up front, and beating up on the enemy's support units. With 3 troop units you also have a big advantage for grabbing objectives so use it! One defense is to force your enemy to dilute his own power by saturating him with too many choices, too many targets, too many priorities. It's a soft defense but it's for real.
I urgently suggest that you replace 1 GH in each pack with a WG. Even with a PF, you gain more overall LD, more PF attacks, and save 6 points for you to get a single combi-something for the 8man pack. Juicy sauce. No extra models, no weird conversions, and no extra points (in fact you'll be at 999 exactly).
With the LF consider reorganizing them by range rather than purpose. Not mandatory but it will avoid situations where some can fire and others can't. Remember your Sgt is going to take the first wound so you will (normally) lose your split-fire early. Naturally that'll depend entirely on which models you have to choose from. Also, since you are limited by model selection try to set up your LF to support your main attack or defense as well as each other. Some players also place their RP with them for extra Ld and CC defense. Unlimited range Psychic powers are awesome for this, but the LF will become a big target and the RP won't be able to move around for better shots.
Placing the RP with the 8man pack is risky because he's not a beast, but he is good and will strongly boost the packs power and survivability and they will become Target No.1 Supreme. If you choose to do that then consider different powers, sure, but remember that LL is an unlimited range plasma gun with d6 shots and no "Get's Hot!". That's very hard to say no to because it's awesome in any deployment, anywhere on the field.