In that case, I would recommend some fast medium/heavies at 6/9 as the 'heavy hitters'. Things like the Lancelot, Ninja-To, Fennec, Linebacker, Ostsol (8M only), Ti T'sang, etc. (Faction permitting). Mix in some solid fast mediums like the Wraith, Blitzkrieg, Legionnaire, Lightray, Crimson Langur, and Stormcrow. Then add some solid lights like the Talon, Firemoth, later Locusts, and Scarabus.
Add vehicle forces that are as fast or faster, like vtols and hover. (a shout out to the Regulator AIV, if your table uses Artillery)
Personally, I would make sure to stick with efficient designs, as much as possible, and look for force multipliers (like C3, satellite support, and Tag/Artillery or SG-LRMs).
In character, a Light Horse/Raiding unit needs to be lean and mean, and 'cheat' (via above force modifiers) when they stumble across heavier opposition or to quickly deal with enemy scouts and flanking forces. Out if character, it helps BV match up to your buddies, without requiring you to have twice as many units.
Fluffwise, look to deal with being independent. This means, IMO, leaning towards energy weapons (somewhat), making sure you have answers to enemy threats like infantry and artillery, and trying for minimal dropship footprint.
