I am struggling to work out how to use the squiggoths' I intend getting.
They can carry a big gun which as monsterous creatures they can move and fire?
They can carry 10 troops which can fire if the squiggoth doesn't exceed 6" in it's movement
phase, but then it's a monsterous creature not a vehicle so it can't exceed 6" so that would be all the time I'm guessing (deffinitly a place to put shootas rather than sluggas).
So they are not really transport / assault mosters at all, they're unprotected gun-platforms?

Now if someone kills the suiggoth it dies, it doesn't blow up like a vehicle, so I assume any transported boyz get off and 'walk away' unaffected by the beasts demise? They could even charge into combat?

If the transported troops get off can the sqiggoth fire its weapon (does it have a crew that is independant of the troops)?

In the shooting phase of a continued melee can the squiggoth target its opponents with a its own frag rounds betting on the 1 in 6 chance it won't damage itself?