I hardly ever loose people (and I have no idea how I lost the last one standing on the roof of the ship in the tower mission. The only outside enemy had been dealt with, and there was a small explosion and she died) and I am using the Scorpion at the moment.
No enemies with nukes yet, though.
I never used Scorpion, but I am assuming it is open ramp design? Well, I constructed Thunderhorse, double the capacity of Turtle, much faster, but open ramp. And I took it to some test missions, because maybe open ramp design have some obvious tactical advantages that I don't see at first glance. First mission against Star Gods, I am to weak to kill them fast, and they are shooting inside cabin, but I have custom power armors, so it is still mostly under control. Second enemy turn, hellerium grenade tossed inside, but only one gal wounded. Third enemy turn, second grenade tossed inside, this time much deeper, 5 gals wounded and most of my equipment on floor is gone, as stack is spawned only 6 tiles from edge of the ramp. What is worst there is almost no hiding spots inside Thunderhorse, you are totally exposed, and when Sectopod arrives in the front of the ramp, massacre begins.
Second test mission against Guild's Supply Ship, some Marsec prick shoots nuke inside during first turn. Out of 24 gals only 2 survived.
And there is ramp itself. Using it cost additional TUs, bleeding your initiative. And when you stand in the middle of ramp going DOWN cost you 8 TU, but going UP cost only 6 TU.
I believe that its possible for both sides to use the same spawn points. I think that they fill up the ones assigned to their sides, then start filling any available spot.
I see that building Summoning Circle was a mistake. I need to demolish it or absolutly prevent enemy from invading my base. But what if I move SC as far as possible from elevator? Will that reduce/eliminate chance to spawn enemy there? Or maybe I will create literally backdoor for enemies to attack me from rear ?