Thanks for the input. From what you've both suggested, I'm now considering:
a) Dropping a single Splinter Cannon from one Venom, dropping another Venom entirely, and adding a Dark Lance Raider.
b) Dropping two Venoms, and adding a Dark Lance Raider, adding three blasters to my Kabalites, and swapping the Twin Splinter Rifle on the Razorwing to a Splinter Cannon, and spending the last few points on Raider upgrades.
c) Dropping two Venoms, and adding a Dark Lance Raider, adding one-three blasters to my Kabalites, and adding one or two Sslyth.
One issue is that I only have access to a single Raider and a single Ravager for this particular event :/ I do have haywire scourges but they're so specific that they seem like a gamble at such a low points game.
Edit: I'm now fairly sure I'll lock in option c), removing two Venoms, and adding a Dark Lance Raider, two Blasters, an extra Kabalite and one Sslyth. I really didn't want to drop the Venom spam but showing up without at least some anti tank seems like a terrible idea if we pair off against mechanised lists.