I got King Poseidon a few days ago.
While I liked the combiner really a lot, I wasn't totally satisfied with lefting a member of the group out of the combiner.
So, I tried to came with an alternative mode where I use Kraken as a backpack/wing module, and Overbite as left arm.
The connecion is rather simple.
You use the two pair of guns that came with Gulf and Tentakill.
Disconnect King Poseidon neck from the turtle's head, and rotate the turtle panel 180° downside, and rest it on the butt.
Extend the connection parts that are on King Poseidon torso that are normally used to connect his back cannons, as you do when you want to rotate them on the front of the torso.
Then, connect the Kraken guns to those 5mm ports.
After that, connect Gulf's guns to Tentakill's.
Finally, you connect Kraken's wings to Gulf's guns, using the lower 5mm port.
You may need to adjust Kraken's arms to the side of the manta ray's head for clearance.