Quoting is making the post huge, so I'm not going to bother
Forceride: Your list looks solid, but I agree that against a list like invasion fleet maybe flame trukks would have been better. Beastbosses can be pretty swingy, but when the devastating wounds go off, they go off

I honestly don't know what I'd remove from my list to squeeze in a burna Trukk or two, it's very tight at the moment.
I also agree that I'd like the Waaagh to last longer, even if with a diminished effect on subsequent turns. It's nice that we have a fairly potent army rule rather than one that doesn't really do anything, but I would also like our data sheets to have more oomph on non Waaagh turns.
The Kill Rig's shooting is pretty good, but I agree that the melee profile isn't ideal and needs more
AP, even if just on the horns and hooves.
Jidmah: I've tried the Hunta Rig and it's really kind of meh. It doesn't have the output of the Kill Rig, and Butcha Boys doesn't really do anything as I'd be getting more out of just disembarking the boys inside. If you're really tight on points and can't afford a wagon for your snaggas then take a Hunta Rig, but it's generally worse than a wagon or kill rig in my experience.
While I do run a kill rig and enjoy using it, it's purely so I can keep using my
FW Squiggoth

if I didn't have that particular model I'd take another wagon or some more trukks instead.