+1 for the Maxus, I have a 2+1 in synthetic and it is faultless, speed loading feature is awesome. Also consider the Winchester SX3, its basically the same gun and fits the same.
I recently got my section 1 cert with a slot for shotgun, wasn't able to order an SX3 but got the SX4 instead. Extended mag tube was promptly ordered turning the 4+1 into a 10+1
The interview will likely be quite relaxed. I think I was asked the difference between a mechanical trigger vs an inertia trigger. It's also good to know your fall out distances for the different weight and size shot; the "300yard rule".
Incorrect with regards to Section 2, but very applicable for Section 1 ammo.
Shotgun ammo doesn't have to be secured. I've got about 3500 rounds stacked up in against the back wall of the dining room.